Sadly this is an N53 engined car. This is BMW's latest direct injection engine and seems to have inherited as many if not more issues as the diesel engined cars. There are numerous posts over on E90 Post about issues with these engines and before MikeHiow turns up to say 'yea but 90000000 people dont have a problem' there are almost zero posts about the earlier N52 engine which seems considerably more reliable.
They seem prone to failing injectors, coil packs and perhaps even more worryingly the DME. It is exactly the same engine as fitted to my parents E60, which at the end of last year, emerged from the BMW dealer with a bill for £1500 for rectifying these issues - and we got off fairly mildly without any injectors being replaced (Though all 6 had to be replaced under warranty before it was 3 years old!)
This is a shame as it is a fantastic engine, so really the best thing to do is to buy one with less than 50k miles on it and purchase the comprehensive BMW Warranty for £500 a year. This gives you complete cover against these problems.
I certianly wouldnt want a 90k miler as you wont get a warranty that will pay (The 'warranty' supplied with the E60 didnt pay, although I knew it was worthless so valued it at zero when we did the deal).
It's such a pity because these issues aside it's a smooth and very economical engine.
http://www.autotrader.co.uk/classif.../radius/1501/page/1/postcode/pl11aa?logcode=p
This car is fitted with the indirect injection N52B25 engine which seems to have far less issues. The mileage is also such that the BMW warranty is available to you in its most comprehensive and lowest priced form.
This is another nice one, again, N52 fitted:
http://www.autotrader.co.uk/classif.../radius/1501/page/1/postcode/pl11aa?logcode=p
I really do think the E46 was the last BMW you could buy a high mileage example of without many worries - the cars still take mileage brilliantly, but these issues can manifest themselves at any mileage and higher mileage stops warranties.
Now moving on from this we'll talk about the 325i itself. For reasons I cannot fully understand myself, there are many, many more 325i's around than 330i's in E90 guise. This gets even more noticeable in 2007-2009 and eventually leads to BMW binning the 330i in Saloon and Touring form in 2010.
Quite why so many people bought a 325i and nobody bothered with a 330i is a mystery to me because the usual identical running costs thing is true with the E90 as it was the E46 before it - the 330i delivers the same economy, same servicing costs yet more performance. Usually I advice to ignore the 325i but as they outnumber 330i's 5 to 1 with the E90 the 325i is a useful amount cheaper (You wont get a 57 plate 330i M Sport for £12k thats for sure!) and far easier to find, therefore you've got more choice.
And it's far from either a bad engine or a slow car - 214bhp and 0-60 in the mid 6's means it still packs a fairly healthy punch.