why my 3000 gt throws so much smoke on 1992 Mitsubishi 3000GT SL

when i started theres is a small amount of smoke and i been tell that is normal but when i stay with my car on and in parking or in a long cross lane or red light it starts and its a lot, then i move in the road and it reduces but never stops.

Asked by for the 1992 Mitsubishi 3000GT SL
Eserini's Automotive has worked on alot of these and the intake valve stem seals crack which allows oil to run down the valve stem into the cylinder. this is where the smoke comes from as it is burned and then exits the exhaust valve. not a cheap job to replace them..
thanx, any estimates or name of franchise shop where i can get an idea?, cause i ve been looking for the parts and i cant find it for my car. Its as expensive as an engine repair?