engine burning oil

my son has a 1997 eclipse w/turbo. he has began replacing factory items with after market to increase horse power and to make the engine compartment look more high tech. the car had been sitting for 10days in which time he gave the car an oil change. I know that he replaced the pvc with an aftermarket item. when the car was started it was blowing oil smoke out the exhaust. My daughter who took the car out said there is smoke of another kind coming through the air vents. what has he done.

if he replaced the pcv with a breather valve instead that can make it smoke under the hood which could possibly come in through the air vents. for the other stuff we need some more details on what mods he's done. the exhaust smoke could be any number of different things.

the smoke coming through the vents could just be because he spilled some oil and its burning off and coming through the vents? was the car driven at all after the mods were put on but before the oil change or was it all at once? one possibility is he was using thick oil before and he switched to a lighter oil which can get out of places the thinker oil cant. see if he got a different weight oil