Have anyone tried the CR-Z brake kit
 

$1500 and it still uses 1 piece rotors? Hard pass on that

Yeah a new stoptech kit is about the same price. This looks like it would be similar to the spoon calipers.

Depends on rotor replacement cost.

I'd say the bare minimum for a front BBK on the s2000 is either the StopTech st40 328mm kit or the Sake Bomb wilwood kit.

If you want cheaper, just buy the 2-piece vented rotors from girodisc.

The main problem with the s2k braking system is heat dissipation followed by heat capacity. Any kit that still uses a solid 1-piece rotor is mainly bling and show (i'm looking at you spoon mono-bloc - works well in conjunction with the girodisc 2-piece option though).

The most important part of upgrading the braking system is the 2-piece rotor.

If price is the main concern, the options for improved on track braking performance should go like this:
1. girodisc 2-piece rotor - $700
2. SBG Wilwood kit - $1300
3. StopTech st40 - $1500
4. after that, pick something from AP-Racing or Spoon+girodisc combo that you like - at that point, price is clearly not a concern

5. I don't see a point in all of the random custom mickey mouse options out there. This is an old car with tons of tested aftermarket options. If you're still looking to mickey mouse together an untested system for something as crucial and critical as brakes, you might want to re-evaluate your priorities.
6. JDM options from J's, TR1, etc. etc. are bling that won't offer much measurable improved performance over the above options. Additionally, you'll likely have fewer pad compound selection options than the #1,2, and 3 options - number 3 will over the most compound options since the pad shape used is exactly the same as the Porsche "big-reds" used on the 964 and 993 models.