[Aussie Mike]

One of the 3 has a funny 3 piston calliper from memory. I think the series 1 had solid front discs as well. Can't remember which one is which though. Stick with the 4 piston equiped ventilated disc front end which I think is series 3. All of the other parts are pretty much the same and they only really changed when they went to the later XJ40 design. The brakes is the main difference between series 1,2 and 3 and it's pretty obvious when you look at them.

Cheers