Hi can anyone tell me the correct off set i need for a set of 8x18, there going on my93 wrx, also what size tyres would i need, to keep the rolling radius the same, currently on 7X17 with 215/45's tahnks in advance

dave

215/45x17 is the wrong size for a classic shape, you should be on 40 profile in that size.

ET48 with either 215/35x18 or 225/35x18 will work. You may have to get the rear arches rolled to clear, depending on suspension and camber used.