After changing the stem seals it will smoke as oil gets into the chambers. I would have waited a while until the smoke died down before parting with cash for the turbo. If the turbo has gone tits up fit a T3 as it's easy to do and transforms the car and is cheaper than getting a T2 unit

When the seals let go on the standards T2 it would start smoking after about 2-3 mins of starting and would then smoke like mad until it was properly warmed up and would then stop