i was looking to buy a S4 turbo2 the car has a fresh rebuild with about 2000 miles on it. it starts up nice and drives great with 2 exceptions....

the oil pressure seems to go below the 0psi and rise alittle when on accelerator

doesnt smoke at idle
smokes alittle after start-up
only smokes when making boost

the research i have done leads me to believe its oil seals or the turbo seals, hoping just the turbo seals, especially if the engine was just rebuilt
what do you guys think? what to pay?
87 turbo2 with under 100k good body needs alittle tlc but not much, hks intake, banzai racing TID , full 3inch exhaust, fcd, upgraded stock turbo $3500

seller says its just the turbo but you never know
opinions please?