Re: 146 alloys - arch clearance (or lack of!)
first off I ran 205/40/17s on standard suspension - only rubbed when 2 up in the back over bumps.
I then changed to 215/40/17s on standard suspension, rubbed with just me in over hefty country lane bumps.
I then changed the suspension to an fk set - back dropped a lot - I rolled the rear arches myself, cut the back bumper away in the corner where it meets the back of the arch, and you need to loose the top screw which holds the bumper in as it protrudes way too much. The arch liners are still in there, but they're almost worn away now lol. The backs don't rub at all - you need to rolll almost all of the arch - tuck it right up inside, back on itself.
A good way to test is when you change the rear suspension, leave the springs out and drop it down, see what the wheels will foul on - bear in mind cornering you will get slight lean so you need to bear that in mind.
Websites are like ********s, everyone has one, and im wary of any bloke trying to direct people into their's