Rapallo
Never heard of the stiffer suspension on sportspack cars, If you are referring to the super being 15mm higher then I see what you mean but most 155's are therefore lower. Supers are rarer.
I'm told the 1.8 silverstone had a slightly more powerful engine (9bhp) than other 8v 1.8's.
1995/96 was a strange time for the 155's with a lot of confusion with the engines, body and steering as you say. There was a thread on 155.com and we never sorted it!!! For example, my V6 is a 95N widebody without the quick rack, Oh forgot to say the V6's throw it all out again!!!
Also some were fitted with spacers to the wheels........but we wont go into that......
wrinx