Okay, So I've searched and searched and cannot find a definitive answer.

I'm looking at some wheels

17x9 et 40 all around. will these fit?

or would I be better off with a staggered set?

17x8 et 20 and 17x9 et 25?

What offsets should I be looking for?

Thanks in advance everyone.

Pic of Car in Question

 

All MINI's have square, not staggered wheels. Look at your drivers side door jamb for what tire was installed form the factory. Then look at realoem with your vin and what wheels they used from the factory and the offset. Look at your owners manual for tire sizes. Then you can look at http://www.willtheyfit.com to see how your new tire and wheel changes from factory. I would stay with tire sizes and offsets that MINI used form the factory so you don't have any fitment issues. There is no info from MINI as to what fits. It also varies based on your suspension if it's lowered.

 

In the 'MINI's in general' heading, there is a tire and wheel section. There are lots of threads there that will help out. 9" wheels are asking a lot. Factory 17's are normally 7" wide with 205/45 tires, though many run 215/45's because there is a greater selection of tires.

Have fun,
Mike

 

On an S I would go no bigger than an 8 inch wide wheel, even with the JCW package the Mini will not benefit from the wider track and added weight.

Light weight wheels and a set of good rubber is one of the best starting modifications you can do to improve your car. The less rotational mass this close to the axles the better.