Relaxcraft

Hi

I've got a 98 impreza sport that needs the clutch replacing. I am trying to get it done as cheap as possible as some of the quotes I've had were sky high, as much as £675..??? Anyway I thought about doing it myself but decided it would be too tricky alone and would need extra tools. I found a website carparts4less.co.uk that sell exedy oem clutch's for £123 with £15 off if you spend over £100 which I thought was spot on. I am gonna give this into a garage and just pay for labour which I've been quoted £150 for. Can anybody tell me what else is recommended to be changed when this is done to get a good repair and avoid future stripdownns??? So far I've thought of:-

3 piece clutch kit

spiggot/pilot bearing for the flywheel

clutch fork dust boot cover

crankshaft main rear seal - I really need to know about this bit, I saw a pack of 2 main front and rear seals. I think the rear goes just behind the flywheel but where does the other go, inside the lower part of the engine or opposite the rear. Also do you need to drain the engine oil to change the seal ???

ANYTHING ELSE..????