One thing i did, which was a bit sneaky but relevant in a way, i checked out the guy i was buying it from...his postcode, what he did for a living etc etc...ok it may sound little i was stereotyping but, Zeds are expensive to run, theyre sportscars and i wanted to make sure the original owner was able to look after it, money no issue. That was a big factor in my buying the car off this particular guy. Plus he didnt actually want to sell, plus he kept taking photos of it, and plus he ended up with tears in his eyes as i handed him my cash...at that point i knew i was onto a winner!! Remember also, 2006 onwards will double your road tax...and some are a little stiff in 2nd gear.
Id agree with what 35oz's has said. Other than that, theyre pretty bullet proof.