Hobibill

Speak up. S4 exhaust manifolds? Free flow exhaust? Chip? Coco mats?
Picture for emphasis.

linderpat

what's your budget?

Landseer

If budget is $160, can fix you up with pair of 85/6 manifolds, delivered.
Not going to be much performance improvement.

GlenL

Use an offset Woodruf key, (or keys) to set the timing on the cams. The left bank is usually late a half tooth. Cost: $10. Power improvement: a few HP...but they're good HP. The car will run more smoothly, too.

Fogey1

Subscribed.

But wait ... You already have a red car in your avatar - how could you possibly want more performance than that? ;-) ;-)

Great looking engine bay, btw.

Imo000

Coversion to a manual transmission is the single best performance improvement for any 928.

AO

What do you mean by performance? Handling? Acceleration? Braking? Ride comfort? Stereo?

Hobibill

Already got the 5 speed. I think that's why even at only 4,5 liter it is so much more fun than the S4. So, you are right but still looking for that single best upgrade idea.

Hobibill

Yes.

davek9

If you are seeking more HP?
I think that's MY dependent as 16valve 928's have diverse engine types.

There has been much discussion on this forum, any big gains especially on early variants get's expensive really quick.

mark kibort

Having a lot of dyno experience with the 2 valver and doing all the mods in succession that you possibly can do, i have determined the best mod is the euro intake system with cams. (without question), (or for major mods, the 5 liter bottom end) . Also, NOS system. its probably the best bang for the buck but kind of a hassle having to fill bottles every month.
next would be the free flow exhaust /cat removal and if you cant do that, then the headers (kind of a tie)
But, i think the best mod you can do for any 928 is the larger wheels and tires.
have fun!

GlenL

Replace the engine with a more powerful one.

I'll go with put on some 18" take-offs from a Cayman or Panamera and put on some top-quality "summer extreme performance" tires.

AO

In that case, the single best upgrade would be to sell the 928 and buy something else.

Thanks for playing... Next!

mark kibort

Then, i think its the big tires, and adding NOS, or the engine mods i mentioned.
do you have a suspension kit installed? the simple performance koni/eibach coil over replacement is an amazing improvement over stock. however, with big tires and wheels, here are huge handling gains to be made. .... Plus the car looks more like it should! (i.e. 3500lbs car on 225s doesnt cut it in my book)

SeanR

Y-pipe.

Not a crappy one fabbed up by your local Midas shop either. Roger sells the one Dave Lomas made and it's the single best upgrade I can think of.