Hey so I have a Volvo s60 2.4t fwd, and I want to get upgraded wheels and was wondering 17 or 18 inch wheels. I would like to add that I will be adding koni fsd lowering springs and struts. so with that in mind in your opinions which do u think would be better

 

depends on your goal. Functionally, I'd argue 17s are the best bet. when you go to taller wheels and lower profile, you get a harsher ride and need to optimize suspension geometry for best possible handling. The choice of wheel also should consider wheel width and offset - at a 17 your +1 tire size would be a 225/45 or so which can ride on a 7.5 or 8 inch wide wheel (my VW CC has 235/45-17s on an 8" rim), at 18x8 you'd be looking 225/40 or so. The next thing is to figure on offset. On a 7.5" your offset should be 38mm and at 8" 35mm.