Seriously mate, be very choosy - take your time.
If possible buy from a fellow member - trace the history etc.
Also double check your insurer doesn't insist on Tracker, so you can factor the subscription in.
If you need any help, I'm sure most on here would assist if they could (even me, a scoobyless member).
Again, a Prodrive Bug should be in your thoughts, they also seem to hold their cash better too.
Charlie
p.s I am now looking at STi's again, never mind the E320cdi I was after lol