Space is very tight in the rear with the 315/680 tires. Attached are some pics for reference. The tub has to be carved out a little bit for clearance near the area where the fender / bumper come together. Not difficult to do but necessary. You also need to remove the front section of the rear fender liner for more clearance. You simply retain the aft fender liner section. It's worth doing the mods to fit the 680s as they are far far superior than the short sidewall 650 or 660 variants. The 275/645 and 315/680 tire diameters measure 25.4" and 27.0 resulting in a ride height of 98/139mm at the factory measuring points. This gives the same rake as on a 997.2Cup but at a slightly higher ride height. I will caution that you can't run these tire sizes on a 996GT2/3 with the street ABS unit as it can't handle the large diameter discrepancy and will go into ice mode. I use a 996Cup ABS which is programmed for 645/680 tires. It's simply unflappable. Hope that helps...

That’s great information thanks, much appreciated. It’s something I’m deinately going to do.
I have 996 rs suspension carriers and 997 cup front and rear
lower control arms, next step is the 997 rsr front and rear
toe arms.
I’ve retained the 996 gt2 rear side subframes though but not sure it’s worth the cost of getting the rs ones or not, I know there is some geometry improvements on those.

You're welcome. You set up is very similar to mine. I'm using the 997.1RS front wheel carriers (same as 997Cup but LCA and tie rod pickup points are about 10mm higher and use 380 brake calipers), 996RS rear carriers (again same as 997Cup but slightly higher pickups), 996RS rear subframes, 997RSR LCAs front and rear, 997Cup front and rear toe arms, 997RSR rear upper arms and 997RSR rear trailing arms with the 23mm bushing on the bottom chassis side. In the front we are using the short 72mm RSR trunnion pin in the LCAs to lower the front roll center slightly and in the rear we are using the standard medium 76mm RSR trunnion pin. Hope that helps...

Great information again, really useful for me I’m going down a similar road you’ve been down I think.
I also have a 996 turbo, im currently modifying the body with a weld in cup style cage and some other mods with the wheel housings etc along with some carbon panels to make it light as possible of which I will eventually put all the modded suspension parts from the gt2 into and put that back to stock. At least that’s the plan 😄

Currently doing the same. Car is stripped and full FIA cage getting welded in the next week or two. Roof still has to come off prior to welding but almost ready. Should end up at +/- 2750lbs when done...

Awesome, get some pics up when the cage is in it will be very interesting to see progress.
It’s amazing how much weight there is to
be saved with unnecessary brackets and bits of trim here there and everywhere, it all adds up!

Yeah, there is a tremendous amount of weight added. We are in the process of drilling out and removing all the unnecessary brackets that are added to the street cars. Basically removing anything and everything that is not in a 996Cup tub. I'll put up a thread on the 6GT forum so I don't clutter it up here.

Cool, that’s exactly what im currently doing.
Ill keep an eye out for the thread.
cheers

what are you doing with your interior panels - mostly the rear carpet

I sold the black GT2 interior including door cards, side panels, carpets, headliner, and the other pieces last week Craig.

I know you expressed interest in the past, but I have a full OEM front and rear clubsport IVM cage for the 996 platform. The rear is a 997.1 cage (with the aft mounted shoulder belts) and the front section is the 996 IVM version. I will be putting this up for sale also. As you know, both are NLA unobtainum now.... It was just pulled out of my car.