would a 18 x 7.5 rim with 215/35/18 tires fit on the rx-7? the offset is 42mm.

 

Theres always a sticker on driver's side that tells you what tire size is suitable for such and such rim size.

its 225 R16 front and 235/R16 rear and then it wider for 17s, i dont remember it exactly.

215 with 18 will infact kill you on FD. Thats because higer center of gravity with loads of power with less tire contact if im right.

 

https://www.rx7club.com/suspension-wheels-tires-brakes-20/fd-wheel-tire-sizing-416251/

 

Oh you want RX7_GRL's Work Emotions don't you?! Sounds like same specs. If that is so... then I would say I'm pretty sure the bolt pattern is not compatible, otherwise she would be using them for her car...