BBS Wheel sizing
 

Will BBS RS wheels off an 1988 944 turbo fit an 1989 911 Carrera?

The numbers from inside the rims are as follows:

7J x 16HZ ET 49 RS 157
8J x 16H2 ET 49 RS 158

I would like to use these without the need of spacers.

TJC
89Cab

offsets
 

If it's an 89 and not a C2 the offsets or ET are:
Fronts 23
Rear 10.6

You will need spacers to take up the difference on those wheels. If you are going to use a spacer, the smaller the better...they can put stress on the wheel bearings if they are to large.

The front offset requires a 26mm spacer the rear a 38mm spacer. To much IMHO.