will l need to do any work to the driveshafts and suspention or brakes??

15'' will go straight on without rolling the arches if its lowerd. no mod to the driveshafts,suspention or brakes are needed

Jays right, but remember that lowering or stiffening your suspension puts greater strain on the body. A good set of strut braces front and back with the 15s and itll corner like its on rails. Your gonna sacrifice some comfort though. When a car is lowered or stiffened you feel and hear much more of the road.

your log book will tell you the different tyre sizes you are allowed to have.
go any bigger then you will have to tell dvla and re register the car

as long as they dont ''foul'' the arch any size you like..but it will affect fuel consumtion..Withering is talking boll ox..

ive seen 18''s on a 106. but you need a lot of other work done to allow for that.

go for 16''s. should get those on with no problems

Er yea, l think youll have to spend a fortune on brakes and suspension. At least your enquirying unlike most 'kevs' who just throw massive wheels on a pefectly good car. In my opinion leave it standard. Ive got an xsi and the standard wheels are really cool. Trust me, theres such a thing as trying to hard.