The final (97 - 00) TPi Cooper S Works had 90bhp which gave 0 to 60 in 8.9 secs and 102 mph however it is not that simple.
The TPi Minis had a very high final drive ratio to meet noise regulations (2.76:1) which reduced performance
example
- SPi Cooper (91 - 96), 63bhp, 3.1:1 final drive, 11.5 sec / 92mph
- TPi all Minis (97 - 00), 63bhp, 2.76:1 final drive, 12.2 / 90 mph
and just to complicate things most performance built engines use 3.44:1 final drive - great for performance but might need ear defenders for motorway cruising
Also the 13 inch wheels which were made available for the first time on the TPi minis (as big wheels were/are the fashion) resulted in a performance loss
- TPi Sports Pack (63bhp) - 12.8 / 84mph
90 bhp is a good figure to aim for as it will be a reliable road engine, higher outputs are possible but the engine becomes less flexible and wears out quickly.
If you want sensible road power and big track / mini run power then a variable boost Turbo is great but complicated and expensive.
So in conclusion (at last I hear you say!)
Find a Mini with a 90bhp engine, 3.44:1 diff and a nice set of 12 inch wheels and you will have a wee flying macine - 0 t0 60 under 8 secs I would think
Thats what I plan to fit to my classic eventually