Advice for buyer

Hey all,
So I am currently looking around for a car to upgrade from my normal 3 series and have come across two different options:
-The first is a 2002 e46 m3 with around 76,000 on it. It has some slight bodywork issues with it, but otherwise drives well.
-The other option I have is a 1999 911 Carrera convertible with approximately 79,000 on it, some slight bodywork problems, and also drives well.

I don't have much experience with Porsche's cars, but I was wondering if anyone could give me any advice about the approximate maintenance costs for these cars if I were to buy them. I would most likely end up doing the actual work on them myself, but minus the labor, how much are parts, how often should they be serviced, should I expect one of them to suddenly stop working, etc. Please keep in mind that I don't mind paying a little extra for a good driver's car, but don't want to spend 20k on a brick.

Any advice about these cars would be much appreciated. Thanks!

try out these links:

terminology -> http://www.bimmerfest.com/wiki/index.php?title=BMW_E46

bmw abbreviations -> http://www.m3forum.net/m3forum/showthread.php?t=307717

So, exactly how much does it cost to "see sig, do it all?" -- and friendly reminder -> http://forum.e46fanatics.com/showthread.php?t=960780

Just bought your non-M E46? Bare essentials maintenance checklist (part #s included) - > http://forum.e46fanatics.com/showthread.php?t=923563

ask the seller for Carfax or any maintenance that has been done to the car. "i don't know" is not a good response from a seller. depending on the Miles/KM on the cars some thing would need to be changed like Cooling system and bushings and brakes and suspension. most e46 have water pump and thermostat failure, just watch out for that.

M cars are more expensive than non-M cars. Porsches are more expensive than M cars. Rennlist and the Pelican forums are good resources if your beloved hails from Stuttgart.

I would probably go for the M3, personally, but I wouldn't buy one with "slight bodywork issues" unless it was immaculate beyond door dings or something. Or if I got it at a good price because a soccer mom had backed into it at Target.