Looking to get a set of techno 20" wheels from a friend in LA but I don't want him to sell or ship them to me if there will be an issue with fitment. I know the offset is different in the rears but will they fit/look more aggressive on a c2s?

He only has the wheels so will I need new tires or will my 20" tires currently on the car fit?

I'm not that familiar with offset measurements....please help

 

Rear C2s 11' et 70
Rear C4s 11.5' et 48

so net 22mm

however the wheel is 0.5inches or 0.25 on each side. thats 6mm

so net net 22-6= 16mm

that THINK its too much.

 

48 is too much.
Your net outboard would be 28mm, since the 6mm is positive also.

If you stick to a 295 rear you might clear.
Dont think about a 305 though.

You could try a 28mm spacer on your stock wheels to see if you like it.

Id worry that it would change the handling balance and make the car understeer.

Would your friend sell just his fronts?