I would also like to point out that lowering springs are nice and the cheaper option (as compared to a coilover kit), but remember the car will be dropped evenly both front and back.
This will result in the front end looking nice and low, with a small gap between wheel & arch, but the rear end will look a little lost, as there will be a larger gap between the wheel & arch. Just enough to play on your mind every time you look at it (well does for me!)
I'm in this predicament at the moment - if I go the Coilover route, I will have to say goodbye to my 3 month old Eibach Pro Street lowering springs, as they will then be redundant! So if you have the money, go for Coilover kit from the start. FULLY adjustable ride height/rebound too.
As for wheels, 17" will fit in nicely without any real problems.
Edit:
Decent lowering springs will lower by a set amount (mm). Cost about £130 inc fitting.
Your OE factory shocks will perish over a time, as they are under strain outside of their usual threshold.
Decent Coilover kit you can adjust the ride height of each corner to the mm!
Will cost you a good £500 just for the Kit - then fitting ontop of that! Not cheap!
But WILL give your ride the ultimate stance, exactly how low you want it to look...
....Ohhh, and dont forget you will then want a couple of Spacers to push out the rear wheels flush with the arches