s2000Junky

Buddy club race spec is the most underrated/unspoken best single adjustable option for under 2k on the market when you factor in the performance, cost, durability and longevity you get out of these before any service is considered, and when you do, service is local and very good. I hit 150k miles on my original set and just had them serviced for the first time. $150 a damper. For a dual duty street car that you want to perform top notch when you take to the track, these are what you want.

DavidNJ

Budget is important. It is easy to spend $20k or more on modifications.

First, plan on brakes. Minimum, larger, floating front rotor, front brake ducts, heavier, vented rear rotors. Urge sells a rear rotor that fits the a slightly modified OEM caliper. Sakebomb sells a kit to use RX8 size rotors with RX8 calipers. Optionally, add a fixed caliper front big brake kit. I doubt you will find it an advantage on the track; some believe it has lower rotor and pad wear, ultimately paying for itself. The big brakes require you to be careful to have wheels that clear. A lot of the 'feel' of the brakes (most of it) is from the pads. Different pads have different coefficients of friction changing the effort needs. Sticker tires and downforce need that to generate enough force. The pads also effect the engagement, release, and control characteristics. Lots of opinions on the forum.

Want to fix several things at once? Get the Wisefab suspension sold by Evasive and others. It is a complete, new fabricated suspension with suspension arms and spindles front and rear. It lowers the car 40mm while keeping the geometry in place (every other solution negatively alters the geometry when lowered). All the bushings become rod ends. You could easily spend nearly as much with piecework solution with worse results.

Shocks are difficult. You want a monotube and the racing ones get expensive fast. The ones sold for an S2000 are really budget racing ones. Ohlins is their very trick TTX that can run $5k per set; sold by PSI. Normally a lowered S2k would need an external reservoir, Penske's 8300 series, about $4300 but possibly more with different pistons. With the Wisefab kit you may get by with their 7500DA, $3300 with the standard piston. They also are base valve shocks JRi would be comparable to the Penske, not sure about the price. Both Penske and Ohlins will gladly adapt their premier racing shocks to an S2000; certain to cost over $10k. You would never be able to take advantage of them. Evasive sells the Eibach R2 for S2000 with springs for about $2800. There are reservoir shocks with nice mounts. However, not too many (any?) real tuning options. Last on my list would be a modified Bilstein PSS. This uses a 46mm piston inside a stamped steel tube (the others listed have machined aluminum tubes). However, they would need to be revalved by Bilstein, Anarchy, Anze, FMAC, etc. They start at $1100 but with revalving and probably adding a Schroeder valve they will be $2000-$2800. The rears have a piggyback external reservoir.

There are lots of brands of springs. Some have a bit narrower wire allowing a bit more travel before minding. There are lots of brands, all with similar prices. 30 years ago spring fatigue was a big issue; racing teams all had spring rate checkers. Now, everybody has access to good metallurgy. Hypercoil, whose springs IMHO represent the best technology in their design. You won't be able to tell any difference between the brands. They were the brand, then a division of Rockwell, recommended by Carroll Smith in his 1970 Sports Car Graphic articles that then became his book Prepare to Win.

Karcepts makes absolutely gorgeous anti-roll bars for the S2000 that have the easiest adjustment available, changing both the leverage and the torsion bar. It is just brilliant engineering. Soft or stiff, tuning the bars is as important as tuning springs and shocks.

Tires are a big factor and are a consumable. With wider front fenders (Evasive has one of their own I like conceptually) and the right wheel offset people have fit 295mm wider tires on 10" wide wheels all around. Lots of different options.

The tires will give mechanical grip, important low-speed corners that dominate most tracks. But as Alonso says, the real differentiator are the fast corners. The exit of Big Bend and the lefthander at Lime Rock can affect lap times, how much speed carried through West Bend is another matter. The question is aero: splitter, rear wing, hood ducts, rear diffuser, etc. It is possible to spend a lot of money here. Many posters here run cars with wings and splitters can give their recommendations. RHR Aero, who runs some of the most aggressive aero in NASA, has been posting blogs about his developments over the winter. He has a Mustang but the concepts are the same. I don't think anyone using aero bits would want to take them off.

More lateral force will need some oil control. There are lots of simple baffles that fit in the pan, Moroso has some weld in swinging door baffles, and Canton has a steel pan with multiple swinging baffles and increased capacity. Threads here on all of them. You can also add a dry sump system. You may need/want an oil cooler, increased differential oil capacity/cooling, etc. Depends on your operating conditions. Are you recording your engine data?

High g's also affect the fuel feed. A fuel surge take such as Radiums or the Holley fuel mat are possible solutions.

A seat that keeps you behind the wheel is important, as is good throttle response. Lots of options here. A containment seat, safest, isn't practical on the street although Sparco's Ergo model has removable side head restraints.

There is another thread discussing different track day cars recently. At least one participant began thinking towing a real race car to the track (a Spec Racer Ford Gen 2 in this case) would actually be a more cost-effective solution and maybe more fun. Used they start at $12k and there have been cars in good condition with spares and trailers for around $20k, less than some of the stuff here totals and with better resale.

So, back to the first question, how much do you want to spend?