If it helps,
You are more than welcome to come and see some options in the flesh, we run a few drift cars with various JZ engines and gearboxes. So we have first hand knowledge of whats the pro's and cons.
I also have a couple of gearboxes you can see first hand to understand whats involved, if nothing else you can come and have a laugh and a coffee for half an hour, and we're only in Colchester, so not far.
Oh and Im not interested in drumming up business for them, Im a customer at the workshop first and foremost and been involved with all sorts of aspects of the UK scene for many years. Just trying to help a lad out.
J.