Wrong wheels on 164

[LoweJacks@domain.elided]

What would be the effect of installing the wrong size wheels on my 164 TS.  
The reason I ask is, about 3 years ago I bought some second hand wheels (15 x 
6)  from an alfa 155 2L.  Looking at the rear struts there cannot be more 
than 2-3 mm gap between tyre and strut.  I cannot assume that this would be 
normal.  If these wheels are incorrect for my car, what would happen (if 
anything) to the suspension or handling. 

Trying to figure out handling problems, so this may be a long shot.


Steve
164 TS
Cumbria UK

------------------------------