[Ant]

Having used a Cobra with a CR Toploader on 3.07 gears, I found it to be to high in First gear, but was good on the track, should have fitted 3.54 gears!
Used a 5 speed Seanz with 650+bhp on 3.1 RE, worked well but first was just a take off gear!

The message I get is from all the post:

Tremecs break synco rings on the track, numerous posts on that subject.
Richmond 5 speeds dont shift good for the track. That rules those out for me!

Toploaders are excellent if you want to change rear end ratios, for road and track.
Downsides are the CR has a very high first unless using a 3.54 RE. The WR has a gap between Third and Top!

Jerico would be my choice or a G-force 5 speed and run a 3.08 with the 5 speed, with a first gear not taller than 2.88/3.04.