Jip, B would be better for you if a VR is a maybe in your future
To be honest, for the small difference in price, I would just get the C. Then if you in future find a nice MK4 GTi engine, you have the option
The C also has some logging options the A and B doesn't have, as mentioned on the website, but this might not be of importance for you.
Setpoints is the "Config points" in the software you set to control optional outputs, revlimiters etc. Nice thing to run VVT, shiftlights, control fans, water injection, basically whatever one can imagine
Get the XMS4C-8AKT - specify the 3 bar AMP sensor if you ever may run turbo. Goes for R 3087.85 incl VAT
If you need an ignition amplifier also, get the XMS4C-8AKTB, which includes a powerfull 2 channel ignition amp at R 3881.63
For comparison, the XMS4B-4AKT goes for R 2670.37, so for just R400 more you can get the top of the line system.
Driving: 2006 Jetta 2.0 TDi Sportline
Upgrading: Lotus 7 replica -
http://www.locostformula.co.za
Racing: Lotus 7 replica racecar - Ford bakkie engine with plastic inlet manifold
Ex: Driving: 2001 Caddy Club, Citi Sonic, MKI 2 Door - 2L with ITBs tamed by PRS2, Toyo Corolla, MKIII Jet CLi, MKII Csl 1600, then 1800, then ..., MKII Gti 8V