Would this off set be ok for my car?

9.5 / 18" 225 30 - AR 11 / 18" 285 30

ET is 52mm for front and 65mm for rear

I have a RS height narrow body 993 C2.

Thank you

 

A starting point:

https://rennlist.com/forums/993-forum/322096-what-size-tires-do-you-run.html

 

So it should fit??

 

should fit...depending on the brand of tires you may need to bring out the baseball bat

 

The brand of the tires is Bridgestone. Do I still need a baseball bat????

 

Probably no baseball bat needed. My rims are ET52 front and ET 65 rears. 225 front and 265 rears. Perfect on a NB.

 

Is the 9,5" and 11" no problem?

Merci!

 

Yes, it is a problem, and no I don't think that they work well at all
Look here 993 info is half way down the page

You will have a problem at both ends, but especially so at the front

 

Also agree that the front will be an issue: the wheel is 38mm (1.5") wider than stock, so all else being equal, it will protrude 17mm further towards the fender lip than a 18x8 ET52 wheel. Easy to verify if you now have 18x8 ET52 installed.
The rear will be tight - Bills charts will guide you . All I can confirm is that 11" ET45 w. 295/30 nicely fit the rear of a WB: 11" ET65 for a NB may be further comprimised @ RS height.

BTY, the max recommended rim width for a 225/40R18 is 9" - you indicated a 225/30R18 .... which I have not seen - but would be less tolerant of rim width deviations.