After a couple of years thinking, I'm sticking with 4 gears for my heavy Karmann '03 with T4 ~175bhp will do nicely. I'm going to spend the cost (~£750 ? ) of a good 911 5speed on my '79 AT 3.875 single sideplate T1. I've scored some T181 o/p flanges, NOS seals and gaskets, a ZF diff, 944 CV's and shafts and only need to find a reliable source of o.e. bearings and shims. I'm playing with other ratio's on paper but I'm undecided.
I use 225/45ZR17 rear tyres (same as 165 15) and would get 100mph at 4650rpm in 4th with this trans. 6500rpm would see 140mph, twice the uk limit, I like to drive for hours on end, (for years to come) without any hassle at 70mph/3250rpm
I'm building for road/track/motorway so I know it won't be a
very quick 1/4 mile
but will get me everywhere, even VW show's in Sweden and Germany somewhere in the future..
Matt