Depends, if you mean the SIERRA XR6, looks like a XR4x4, RWD, and 3litre Essex V6 in it.

SIERRA XR8s looked similar, South Aftrican GrpA Homologation special, 5litre V8 from Ford Mustang and T5 box.

The more recent Aussie XR6s and XR8s are totaly different cars all together, and the newest shape versions of both look VERY nice, and the XR6 Turbo is 3.5litre 24v straight six turbo, comes with a massive GT40 turbo and a shitload of power as standard