I have 205/45/17 contisport tyres on my bmax. However I find them to be quite noisy and seem to feel every bump due to them being low profile. If i changed the tyres to a 205/55 or 65/17 would this be a problem or would they fot ok?
Yes this would be a problem.
Fitting sizes and ratings of tyres not approved by the manufacturer will not only void your warranty but can also invalidate your insurance. Bottom line is that if you fit non approved tyre sizes and have an accident your insurance company may refuse to pay out AND the police may prosecute you.
The only approved tyre on 17" wheels is the 205/45 R17. I sympathise with your wish to use other tyres, mine has 195/60 R15's fitted which gives a much better ride. My advice would be to get some 15 or 16" wheels and tyres and sell your current set on ebay. If you do this get the dealer to recalibrate the speedo for the new tyre size if necessary