deffo. must if high mileage. even if it looks ok, id do it. worse case.. say you change the clutch, then in a few months the fly dies. then its new clutch again plus fly , plus labour again.

while the box is off, it makes sense.
 
yes it does, thats why I was thinking going with SMF? To be honest I havent looked into how hard a job it is to do, on cars without front subframe its not too bad, but with can a nightmare, rear wheel drive is great, can do a merc sprinter van in about hour and half, all back together.