Welcome to the board.
Best car I have ever had mate. The main problems I have is the attention from women the car brings and the jealous glances from divers of lesser machines, and people asking what the hell it is all the time.
Seriously though, rear calipers and steering racks on early cars can be a bit of a weak spot. Distributors are a weak spot too. The only one that is going to cost you the earth is the steering rack (£1000 from Mazda, but that won't phase you if you have got an Audi) as cheap(ish) work arounds and pattern parts are available for the other problems
Both banks of cylinders have a tendency to weep oil from the rocker gaskets into plug holes, the HLA (Hydraulic lifters) have a tendency to get clagged up a bit and rattle (which can usually be solved with a good flush out and some quality oil).
You would have to be unlucky to get all of these problems on a car and overall I have to say that they are the usual Japanese picture of reliability. I have had mine for 6 months and 10,000 miles and nothing has fallen off yet. not bad for a car that is 11 years old.
Go on, you know you want to get one.