Wheels & Tires - ok need a little help for tires

did a search and cant really come up with anything. i bought 4 18x9.5 adr m-sports in hyperblack for my 02 firehawk. my car has the eibach prokit on it so its lower then stock. ive been looking into some tires but cant figure out what size to get, i definatly dont want the wheel to be flush with the tire, like to have some protection and the better look of the tires sticking out a little past the wheel. so, would 275/40/18 be good for all around the car?

did a search and cant really come up with anything. i bought 4 18x9.5 adr m-sports in hyperblack for my 02 firehawk. my car has the eibach prokit on it so its lower then stock. ive been looking into some tires but cant figure out what size to get, i definatly dont want the wheel to be flush with the tire, like to have some protection and the better look of the tires sticking out a little past the wheel. so, would 275/40/18 be good for all around the car?

You relay need 275/35/18 or you timing will be out (Speedo will be out a bit).

I run 275/35ZR18 on my 9.5's . . . PERFECT! :) And the speedo won't be off.

so if i went 275/40/18 id basically have to get the computer reflashed? i can do that no problem but if i were to go 275/40/18 would i have clearance problems since i have the pro kit on my car?