wheels spacers to clear my coilovers.

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i found a set of wheels that are 16x7 and 16x8 w/ a 35 osset all around the seller thinks. i know i will need spacers to clear the coilovers and went to opt auto to look at the h&r spacers. i searched and read all i could bout using the spacers and i gotta go back and read more. anyway i know i would need a 5mm spacer up front and shuold i get a 15mm for out back? the front tire size is 205/55 and the rear is 225/50. they nice wheels and selling for $550. the spacers are pricey so should i just get other wheels to clear them or buy these and spacers and does anyone have problems w/ spacers? thanks, hope this topic isnt a topic that has been asked a million times.