I've bent my old Escort axle. Got me thinking time to get modern (ish). So do I go Sierra diff and arms, if so which one? What is the better one? splined or bolt in, plenty about down here, just need some advice. Something just jumped into my mind, how about the MX5 diff back axle wotsit. Thanking you in anticipation, Steve.

You only need drum rear on a light car
However I've only seen bolt on Sierra LSD
If your running 13" wheels you need a shorter rear calliper handbrake spring, the smallest wheel fitted to the Sierra was 14"

Pretty much the best site for sierra information is here

http://www.super7thheaven.co.uk/blog/differentials/sierra-rear-differential/