Red Mx5 - Couldn't agree more about widebodys. We're doing a widebody on our WRX, but we also have JIC Magic coilovers, Racing Brake BBK, Porterfield brake pads, custom sway bars, etc. The purpose of the widebody is to fit 11" wide front wheels and 12" wide rear wheels to make the car handle more neutral. The cost of the widebody along with all suspension mods, custom wheels, and R-compounds to fit 11"/12" wide wheels is more than most used S2ks cost. Not worth it unless you are VERY serious.

B Money - Expect a little more grip, but the most grip is with R-compound tires. A good setup is the Comptech front sway bar, remove RSTB, R-comps, and KW V3s once you really know how to drive. Track pads, stainless brake lines, and brake fluid change help as well.

 

How do offsets on wheels effect handling? I can imagine the lower offset =wider tracking which in turn I imagine would help in traction.

Would a few mm in this help?

Right now im running 7.5 +48 and 8.5 +54 on prodrives, which is a little different than +55, +65 offsets of stock.

IF (I know we cant) we ran like 0 offset would that result (for sake of argument) in better grip?

 

Wheel spacers or anything else that increases the track will reduce total weight transfer, and if all else were equal, that would result in increased grip. Downsides include softer effective shock, anti-sway bar, and spring rates, greater loading on the wheel bearings, and potential issues with things like the camber and toe profiles. I've considered trying 5mm and 10mm spacers on the back of the car just to see what the results would be, but after we installed the KAAZ I was so pleased with the handling that I've been slow to even think about changing anything else. When you're building a car to a set of class rules, you want to make the track as wide as the rules allow; For example, the SCCA allows a 1/2" track increase (through wheel offset or spacers) in the stock classes, so that's how much you want to increase the track. It doesn't make a huge difference, but when you push all the rules to the limit the small changes add up to better times (lol, assuming the driver isn't the weak link in the chain ).

I can't remember if this has been said yet, but the biggest improvement you can make in the cars handling is usually a good driving school like Evolution. I've been autocrossing for decades, but the Evolution Schools I've attended with the S2000 have made a bigger improvement in performance than all the mods put together.

 

Don't know if this has been mentioned yet. Buy or borrow a book called "Race Car Vehicle Dynamics" It's not just for racing by the way.