996 Smokes on Startup

[porsche911gt3rs]

I've had my 02 996 C2 for 2 years and it now has 40,000 miles. While it was at a indie shop for the airbag light not coming on at all, I decided to let them change the oil. I already had the OEM Mann filter and dropped it off to drive the car home later that day. After the 20 mile drive home I parked the car for 5 minutes to open the garage and move some things and when I started it up it smoked BAD, probably worse than I've ever seen a car smoke. I immediately turned it off to check the oil and it was almost half an inch above the max line on the dipstick! After fuming about what kind of a dumbass it takes to put that much oil in a car and what it could have done to the engine I siphoned at least a quart to a quart and a half out of the car. With the oil now at the full mark I started the car and it idled low at about 400 RPM for 20 seconds or so and smoked just as bad for about a minute. I drove it around the block and brought it back and it wasn't smoking anymore. Thinking it was fixed it sat for 2 days and when I started it again it still smoked though not nearly as bad. I'll have to see what it does when I start it today. What damage could this have done to the engine? Can too much oil cause an engine to do this? After this there's no telling if they even put in Mobil 5w40 like they said or even changed the filter. Sorry about the length of this but I'm just worried about the state of my engine which is almost as much as I paid for the car.