yeah 14x6 will be fine, i need to update my site with my more current knowledge
the disc and calipers (girlock) are good
but for a cicuit car id toss em, on the same page im pretty sure it has a conversion for hi-lux 4 spot calipers, this is what i have on my road car and they are f'n unreal
you use pintara VENTED discs, these need some machining to fit, both to open the centre and to thin the disc if required
and hi-lux calipers which also may need some machining of the body of the caliper for clearance
i did not install these my bro-in-law did, and if you have more questions about the install (if the info isnt on my site, dont really remember), just ask and ill find out, no probs
and something else thats on my site id recomend is the bluebird disc over drums for the rear if you have h160 or h190 diff (also recommended diffs to use

)
and a sunny booster