to lsd or not to lsd
 

is it worth purchasing a Limited slip differential for my roadster, i don't have a donor vehicle but i am using a bmw 1.9 engine from i z4

I think the lowest powered engine from the BMW Z4 is the 2.0 and thats around 150bhp. So its well within the practical / fun range, without being a handful. Its on par with a C20XE Redtop, or a mildly tuned Zetec. You'll be fine without a LSD. Infact I'd go so far as saying it would be more fun and a little more predictable.

meant to type z3

Oh, well thats even less power then. Unless your going to be racing it in competition, I doubt your ever going to need it. I'd say its not required unless your clearing 200 ft.lbf

well i might be as i'm currently trying to scrounge a supercharger for it

Wow, let me know than, because we are using almost the same engine, I'd realy like to know if you managed to fit it with the supercharger :)

there is an american company that supplies supper chargers for this engine but the whole kit is about 4 grand

I think I read some where that the car is to light to make use of the LSD so it's not really worth having one?

most ford sierra lsd's are shagged anyway. finding a good one is like finding a petrol station that gives the stuff away for free.