You'll want a proper diff rather than some Supra one. What I gather from talking to a few people is the Supra diff isn't really any better than a health 7.5" diff, plus it costs more to build by the time you buy all the add on kits needed for them to be fitted an not explode. If you are 2WD already I'd use your existing diff if it's in good condition.

Barra now does a front diff that is his take on the old R&D item.

As for sequential boxes a Quaife 6 speed one will be something like £10/11K plus VAT


That's what this car has with 500bhp.

If you go for 800bhp you'd need to talk to somebody like Rod, but I suspect you are into 9" motorsport diffs etc