mr.t0fu

A bit of background: As requested, I'm posting all the parts that I bought in order to do the 718 GT4 bumper swap onto a 718 GTS. Please note that I had help from my SA and parts guy at my local dealership so YMMV. There may be missing parts, I don't know (I don't think so) but I encourage anyone attempting this to confirm everything with their local SA/parts person. Do not assume my list is 100% correct. I'm too lazy to retype out all the parts, which there are many, so I'm just going to be posting screenshots of what I purchased.

Additional thoughts and considerations:
1) I don't want to get into the "you should have bought a GT4 from the start debate" - I bought my GTS at a deep discount prior to the market going crazy and at the time there were no PDK GT4s (I really wanted the PDK for the track) so those are my reasons, take them or leave them.
2) My car is a track car so my main motivation for the GT4 front bumper was to balance the GT4 wing that I have coming, plus it looks sexy AF.
3) In my opinion, the GT4 bumper should not be run without balancing the rear aero, be it the factory GT4 wing or some other means of adding rear downforce, again my opinion, YMMV.

Finally, the meat and potatoes: Below is a screen shot of all the part #s that I purchased, again this list worked for me, if you are going to attempt this confirm it with your SA/parts person. A few thoughts on the parts and the installation process:
Parts First:
1) I don't have a front plate on my car so I deleted the licenses plate kit (saves you some $).
2) I wasn't sure if the daytime running lamps were the same parts so I bought them, just in case. Turns out they are so I ended up returning them, saved a decent chunk of change there. The wiring harness is also plug and play, but I did not buy a new one, I re-used it from my GTS bumper.
3) Some part #s are a "package". For example, the bumper, 982-898-041-H includes the bumper and the side spoilers. They can also be bought completely separately, obviously, when you do that they have different part #s. This is the importance of having your SA/parts person verify these parts otherwise you end up having double parts (like I did).
4) You need to confirm before hand if you have headlight washers, you have the option of both.
5) I'm not sure if you can chose to have the cutout for the front park sensors. Mine didn't and I currently have the front sensors unplugged. It's not a huge deal to me, again track car only.





Install:
1) The first decision to make is if you want to the run the center radiator venting the GT4 style, which goes up, or the GTS style, which goes down. If you decide up, then you will need to buy the center radiator from the GT4 or an aftermarket one as well as the associated ducting and brackets (this is what I did). If you decide to vent down, you will need to cut holes in the lower splash shield if you want to maintain a similar venting scheme to the GTS. IMO the splash shield was designed not to have holes cut in it (from an aero perspective) so I went with the GT4 venting up.
2) My fender liners did not share the same screw/attachment points on the inside of the GT4 bumper so I bought GT4 fender liners and everything lined up. I bought these after the fact so they are not on the above list and I do not have the part #s.
3) The installation, on my car, was very straightforward and everything bolted up without a problem aside from the few notes above. Here are a few pictures the finished product:






I am very happy with the way it turned out. I can feel the aero affect and I have a very unsensitive butt. I'm sure there are questions, ask away, hopefully I can answer them/help. Thanks for reading!

martopoulos

Great job! Thanks for the write up! I just wish I knew this was possible before I replaced my bumper + lost a chunk of change on a terrible fiber glass replica that got junked. That's life.

gurneyeagle

Looks great! Love that front bumper.

Would you mind sharing what it cost you?

I did a similar thing with a 370Z I owned a few years ago when I changed out my front bumper to the Nismo bumper. Like you, changing to the proper fender liners made everything match up better.

Total cost for that conversion was about $3,500. I would assume the “Porsche tax” made your conversion a bit more than that. 😜

mr.t0fu

Don't mind at all - the total cost for the parts were around $5,500 - that was all OEM, new, parts. That does not include paint and labor since those costs can vary greatly. I will say the time to put the bumper together and get it on the car was about 4-ish hours.

OldJedi

Hi, just curious if you ever decided to put on the GT4 side intake covers and rear spoiler?

mr.t0fu

Yes, I installed a rear spoiler. It's been on for around a year and a half. A must have in my opinion. The aero needs to be balanced. I skipped the scoops as I didn't see a huge gain. I'm sure there is some ram effect, otherwise Porsche wouldn't have done it, but it seemed fairly minimal.

OldJedi

Thanks for the quick reply. Did the OEM GT4 rear spoiler bolt up without any problems? I was going to order one for my GTS but have read on here that the GT4 part will not bolt up to the GTS. Not sure why.

mr.t0fu

It doesn't bolt up directly to the GTS hatch. The GT4 hatch has cutouts for the wing riser support. DBJ makes an adapter kit if you don't want to buy a GT4 hatch.

https://designsbyjacob.com/collectio...n-wing-adapter

Lots of people use this adapter successfully.

OldJedi

Thanks, I was talking about the small pop up spoiler and not the wing. The spoiler on the GT4 does NOT raise up at speed because of the wing but it does on the GTS. I just wondered if you changed the spoiler along with adding the wing? And if so, did the GT4 spoiler bolt up to the GTS mechanism that raises the spoiler?

mr.t0fu

Gotcha, no I did not.

OldJedi

^^^^^ OK thanks

wdr911

OldJedi,

Dave here……actually in Austria these days.

I to woukd like to add a higher rear lid piece in place of our standard lid on the Cayman GTS and S .

in looking at the GT4 RS…..the lid piece that does not lift / Raise up would be a “great addition” to our Caymans. Given I don’t track my car I am not concerned that it does not raise at speed.

In addition, it also has a third stop light would be a nice add, especially if we were able also hook it up as an additional third stop light to function. Or since we have to paint the new piece, the third stop light opening could be filed in some manner to eliminate the “third stoplight” opening in its entirety.

See pictures. The third and fourth pictures will give you a better idea of how it would look versus our version of lid which when in resting position.

We can chat when I return home later next week.

best regards

D

OldJedi

Thanks Dave, I hope you are enjoying your trip.

I think the rear spoiler on the GT4 and GT4RS are the same overall height but the GT4RS has a third brake light built in. I just have not been able to determine why the GT4 spoiler will not attach to a Cayman GTS. I know that the GT4 is fixed and will not rise up but will it bolt up to the GTS mechanism?? I do know that the spoiler from the Spyder will bolt up to the raising mechanism on the Boxster GTS, just not sure why the GT4 spoiler doesn’t do the same on the Cayman.

Talk to you later. Be Safe.

mr.t0fu

@OldJedi You may already know this, but it looks like the lower piece of the spoiler is a different part #

GT4 (part 2): https://www.porscheatlantaperimeterp...rimLevel=33984
GTS (part 3): https://www.porscheatlantaperimeterp...rimLevel=34001

Whereas on the Boxster GTS/Spyder, it's the same part #
Boxster GTS: https://www.porscheatlantaperimeterp...rimLevel=35920
Spyder: https://www.porscheatlantaperimeterp...rimLevel=33929

I suspect the GT4 spoiler will not bolt up being that they are different part #s, but this is just pure speculation.

mintynfresh

Any idea how this breakdown would work from an S > GT4 bumper? No center radiator or venting on the S.