what wheels will fit my car??

Ive just recently bought a rover 200 and want to start modifying it, ultimately getting the usual, bodykit, exhaust etc etc.
Im wanting to get some alloys but im not sure what is the max size i can have for my car?
Is there anyway of finding out?
Im quite new to all this so excuse me if its sounds thick

Ultimately you will need to find out from a wheel shop, or tire shop. You have to understand that there are many different circumstances that can lean wheel selection. You'll have to select a wheel that will leave you enough meat for the tires (so your rims wont get bent when hitting pot holes, etc.) The offset will also play a part in the fit and look of the wheel. Remember too, that aftermarket wheels, when significantly changing size, will have a change on your speedometer, and overall ride of your car. You may notice more road feel with a bigger wheel.