What diff would you guys recommend?

[jmc330i]

Using 205/55x15 tyres, a 3.91 diff will give you 3850rpm at 70mph.
3.46 gives 3400
3.25 gives 3200
3.15 gives 3100

Just to give a comparison, a standard 325i Sport will be at about 3200rpm at 70mph, so a 3.25 diff would make sense.

The 3.45 diff will see you running about 3500rpm at 70mph, which isnt too bad and the acceleration will be quicker
You could run the 3.46 in the meantime until you find a good 3.25 or 3.15 diff.

[ballin]

you could be right!

i do appreciate all the input lads, very much appreciated!

the exhaust on there atm doesnt help things as its unbearable @ 70mph due to the noise, which in turn makes it fell like its revving at about 7 grand!

Once i get that quietned down (thursday) ill be able to see if a 3.45 will be good enough! Dont really wanna be changing it twice thats the only thing

[jmc330i]

Dont really wanna be changing it twice thats the only thing

Its one of those jobs that nobody likes doing, but once youve done one, its not that bad.

I found it pretty easy and almost enjoyed it, until I broke my fingers undoing the prop bolts