You'd want to upgrade your 18" wheel equipped car to the Brembo brake package, which comes with 19x9" wheels instead of the 18x8" wheels the base GT has. You can't just use the 19x9" wheel size without upgrading to the 2013 package that came with those wheels - and you have to upgrade everything. There are different spring rates, too. The extra inch of wheel width is critical.
Click on the thumbnails above to see the base GT springs (left) and the Brembo equipped GT's springs (right)
There are a few unusual modification rules in "Stock" that you would want to exploit, to be competitive:
- Double adjustable shocks. You can spend insane amounts of money on custom monotube doubles in Stock. I've seen $10K shocks on Stock class cars. It is nuts. The shock rules are weirdly written, so be careful and order from a reputable shock dealer. Personally I think spending over $2K on shocks in Stock class is nuts.
- Maximize tire width on the stock sized wheel. I've seen the Shelby GT guys smashing 285/30/18s on those itty bitty 18x8.5" wheels. I think there's a 295 you can squeeze onto the little 19x9" wheel. As nasty as it looks, it seems to help for Stock class autocrossing. And oh yea, they need to be Hoosier A6 tires or don't bother. And oh yea, they'll last about 30-40 runs.
- Lightweight wheels in the stock size. Custom 1-, 2- or 3-piece wheels to minimize weight. You can play with offset by 1/4", but otherwise the wheels have to be the exact same diameter and width as stock (or the optional stock package you upgrade fully to).
- Alternate swaybar... at one end. You can add any aftermarket swaybar you want, even something totally custom, but only to one end.
That's about all you can do. So now you have $1500 gumball tires with a very short lifespan, $2-10K in shocks, a $200 swaybar, and maybe even $3000+ in custom lightweight wheels in the stock size. With marshmallow stock springs, skinny wheel widths, and no front camber or adjustment. I've driven cars like these and they handle like ass. But hey, "you're saving money" by running stock class!
I feel the Stock is one of the most expensive classes to run in competitively, not only because the weird limitation to allowed mods tends to
eat tires at an alarming rate, but also because there is a relentless amount of car updating that takes place in most classes. A new model comes out that has an extra 50 hp? Time to sell your old car and get the new one. Oh, there's a special addition model now that has another 1/2" of wheel width! Time to upgrade. It can get a little crazy at the top levels.
Other classes you could run include:
- STX (hopefully STU someday soon)
- ESP (just don't buy a Watts Link that isn't made by Steeda or Fays2)
- SM (don't plan on winning)
- RTR/FS or RTR/ESP
I think of these 4 choices (FS, STX, ESP, SM, RTR) the only logical answer at the moment is ESP. You can still run the giant gumball R compounds and fancy shocks, but you can add negative camber up front to keep from shredding the outer shoulders, and add spring rate to keep the car from flopping around like a fish. If or when these cars are
moved up to STU class that would be an even more cost effective option. And if you want to run on 140+ treadwear tires but utilize the mods from one of these other classes (FS or ESP), try the new RTR category. Saves you many thousands a year in your Hoosier budget by switching to ST tires.
Good luck,
