ok just after reading the first few lines get it to smoke up again and get out and waft some smoke in you direction if it stinks then there is a problem otherwise there is water in your exhaust the condensation forms up sits in your mufflers when it heats up turns to white smoke the down side is to this the water mixed with the exhaust gasses turn to an acid and melt the mufflers from the inside
i had some little shit kid put a hose up my exhaust and i was freaking out how much smoke my exhaust blew i was filling the street in the end i found it was water give this a try if it smells like steam your all good
other than that has the sump been changed from rwd to fwd as the rwd sumps dont have the baffle plate in the bottom and thrashing makes the oil slosh turn to vapor witch inturn will get to the combustion chamber and not burn thus white smoke i hope any of this helped
cheers
mat