Remember 1 thing, if you use a 45 series tyre on a 17in, it is basically the same if go 40 series on an 18in wheel. It would be the same if you use a 50 series on a 16in wheel.
The best advise is buy the wheels first then change the springs afterwards, if you do it the other way around you will never be happy.
Trust me l did that way and the car was prefect.
Have you seen cars running around with big wheels on them and there is about 3in clearance between the tyres and the guards on the front, that standard height and they would handle like a bucket of shit, just look as you are driving down the road, you will see them and you think f#*k l am glad he is driving that and not me.
I measure up my 14in celica rim against the 18in l have on my ute and it the same size.
Roscos
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