Offsets That Fit my '99 Box

[bar10dah]

I have OEM 7.5 x 18 w/50 mm fronts and 9 x 18 w/52 mm rears. I believe they're called Turbo Twist IIs. I really like the looks of these wheels, but recent damage to one of them, plus the fact that I'm not sure the other three are even straight (other party's insurance was going to get the damaged one straightened), has led me to start looking at some aftermarket options.

The wheels I'm considering are 8 x 18 w/ 54 mm fronts and either 9 x 18 w/ 43 mm or 10 x 18 w/40 mm rears.

Appears the new fronts will have 10 mm less inner clearance and extend the outside edges by 2 mm from my current wheels. Will that work/fit? How about fitment after I install my ROW M030 suspension?

Which option rear should I select, 9 or 10 inch width? 9 inch width would be 9 mm more inner clearance and stick out an additional 9 mm from my current wheels. 10 inch width would be 1mm less internal clearance and stick out an additional 25 mm. At this time, I'm leaning towards the 9 inch rear.

Those numbers are the differences from my current rim/offsets. But since there's a larger width rim that was available from the factory (8 x 18 w/50 mm and 10 x 18 w/47 mm), can I use those numbers to help confirm the max widths/offsets I can use? If so, the differences as compared to the larger wheels would be fronts 4 mm less inner clearance and outer edge reduced by 4 mm. And the rears would be 17 mm more inner clearance and reduce outer edge by 9 mm for the 9 inch width. And 5 mm more inner clearance and stick out an additional 5 mm for the 10 inch width.

I created this chart to help understand what each wheel size does to the inner/outer positions.

My main priority would be fit. I don't want anything to rub. Especially with the ROW M030 suspension on it. Secondly, I'd like to keep as close to the stock appearance as possible. I really don't want the wheels sticking out horrendously from the body. Opinions would be helpful. I hope to order these wheels this afternoon.

Additional pics of these wheels on an arctic silver Boxster.

[Bob B]

I'm currently running 8&10X18's on my '00 Boxster S with the stock suspension. 52mm and 40mm offset, respectively. I haven't had any problems, but I'm thinking of lowering the car.