If your bag(s) are not tagged through to SIN You are asking for aggrevation ...you and your bag(s) will arrive at KUL Satellite terminal. You will then have to take train to KUL Main terminal pass through Immigration collect your bags...pass bags through customs x-ray...exit to Main...go upstairs to MAS counters to recheck yourself+bag(s)...take train back to KUL Satellite Term...and only then go J lounge for a beer...is it worth it??

PS: You haven't mentioned how much time you have between flights...so perhaps this is an exorcise to kill some of that??