Forget all the stuff written on here, folk usually post because there is a problem, if things are going well they generally don't. So reading on forums like this may give a very false sense of what is actually good/bad with the cars.
I've got an LE and it is bleedin' brilliant!
A lowly 1.9jtdm, but it certainly holds its own against the 320d/A4 boys and girls (after a gentle remap....).
19" tyres are always going to be expensive, understand that from the beginning and all will be well. Get the geometry set up properly from day one (at the cost of around £40) and all will be well.
1.9 diesel if economy and mileage is an issue, 2.4 if you can live with near petrol mpgs, but it has huge grunt and makes a nicer noise than the 1.9 (for a diesel).
Great cars, on my second 159 (after a 12 month gap in a GT). Love them to bits, nothing out there looks like them, feels a very special place to sit. Mines on 97,600 miles and rising rapidly.
Choose wisely, don't just grab the first one you see (because you will want to!!) and you will love it.
PS: Get an LE, much more exclusive than the Ti, just don't tell the Ti boys and girls, they get annoyed....