I've just torn down my WR for some much needed attention. It is three seasons old and needs new plastic, brakes, chain/sprockets, etc... It runs and starts great. No issues at end of last season except for water pump seal failing and dripping out the weep hole. Parts for that repair on order. My question is: Should I "freshen" up the motor w/ a new piston/ rings during this tear down just for good measure or don't fix what isn't broke? Thanks.