If I have 10's on the rear now will I be happy with 9's
 

?? I love the look of my 10's will I be disappointed in 9's? will the handling change?? do I need to redo the alignment?? thanks Trying to figure out replacements for my damaged wheel. Lots of good stuff on ebay right now.

Depends on the wheels and tires.

on 993 factory wheels, the 10x18 rear is only a few mm more to the outside than the 9x17--most of the increase is on the inside.

Some tires fit fine on a 9" wheel but if you have anything larger than 265 they probably won't fit at all well. I would not go backwards on wheel width. Even if you can't feel the diff it will bug you.

You will not need an alignment change, but depending on how aggressively you drive (not talking road rage aggression!) you may notice a change in the handling. I personally would not go to 9" in the rear (esp if you are coming from 10")....you will be limited in the tire sizes you can use and may also want to use spacers to make the wheels "fill" the wheel wells. BTW, if you can locate just the Boxster 18x9 ET50 rear twists you can use them as fronts...so you can make up a factory set of 9"/10" twists :)

Why would you consider 9s? They are not the proper size for an 18" wheel on a 993, not to mention it looks ridiculous. At most you'll save a couple hundred $?

+1. If it were me, I'd want the correct wheel sizes. Either save up or wait for the correct sizes to come up on the used market.

Thanks for the replies, and these were the answers I needed b4 making a bad decision. Thanks rlisters.