Compared to stock 16inch wheels, the you wheels will stick out the following amounts:
(Stock Front 16x6.5 +55, Stock Rear:16x7.5 +65)

Front: 18x8 with +45 offset
Inner Clearance: 9mm Less
Outer Position: EXTEND an extra 29mm
Rear: 18x8.5 with +48 offset
Inner Clearance: 4mm MORE
Outer Position: EXTEND an extra 30mm


Front: 17x7.5 with +45 offset
Inner Clearance: 3mm Less
Outer Position: EXTEND an extra 23mm
Rear: 17x8 with +50 offset
Inner Clearance: 9mm MORE
Outer Position: EXTEND an extra 21mm

you can use the offset calculator to get an idea for other rim sizes:
http://www.1010tires.com/wheeloffsetcalculator.asp

with rolled fenders, those sizes should clear (depending on tyre size and amount of camber of course).