So if I reduce wheel size from stock 19's to 18's does this mess up anything with the speedo? Do you need to go with profile 40 on front and 35 on back instead of 35f/30r to make up for the diameter difference? Any con's I should know about?

 

It may be difficult to find a wheel that will fit over the front brakes. Why are you trying to go to 18's? Cheaper tires?

 

Yeah cheaper tyres and better performance I thought? 19 inch tyres are limited in options and expensive here in new zealand. Its got a et 6+ offset. That should fit, right?

 

You're going to have to test fit. That said, I assume the factory wheels (I haven't looked) are probably +30ish in the front and +55ish in the rear. A +6 will likely stick out of the fender, but I'm still more worried about the brake clearance. Try bolting them on, that's about the only way to know for sure.