I say seals.
But one thing you MAY try idk if you should im not an oil expert but when i had my e21 320i it smoked and the e21 people reccomended to substiture a quart of lucas oil stabilizer and use 20 50 oil.
IT HELPED! smoke was reduced by ALOT, untill the car warmed up abit though.
Man i Miss that car
i bought it for fun and being greedy decided to make money on it had it only for about a month.