The seal kit has every piece of rubber in the brake, which is why I'd always do it, for the sake of £6 you might as well! Havn't read this so I dunno if it's any good, but here goes: http://www.trials-forum.co.uk/wiki/Bleeding_Hope_brakes I use an adjustable spanner to straighten mine, just using the caliper as a guide and bending it straight. If it keeps going back it might be time for a new rotor though, mine tend to stay straight. EDIT: If you decide to polish the pistons, you can usually grab the bit where the magnet sits with a drill chuck and use that to polish with a cloth and some autosol.