Just wondering what would be the best pressure for my tires, I have a 2003 E46 M3 with the 18'' M wheels, with Contisport contact 2 tires

Depends.

Only way to get "optimal" tire pressure is to take tire temp readings after driving your car.

I guess that depends on what your optimal driving style is.

Fairly aggressive, looking for good traction and decent mileage for myself = 36 front and 42 rear at cold readings.

If you want a less bumpy and stiff ride, then go with the factory settings. Best bet is to just try out a few different scenarious yourself and make sure to take cold and warm pressure readings. Generally you want the front to be lower than the rear for better steering feel.

just my two cents

Are you talking about pressures for the street or for the track? For the street, the factory pressures are good - located on the inside of the driver side door.

For the track, I shoot for about 36psi when the tires are hot.

36 psi hot sounds way too low for everyday driving if you ask me. I've never gone by factory psi specs on any car I've owned - that of course has to do with my own personal driving style too.

your best bet is to just figure out what works best for you and too keep track of your progress while testing.

See, you guys are throwing tire pressures out there, not realizing that "optimal" tire pressure depends on several things: ambient temperature, aggression level, elevation, etc.

He needs to get a laser temp reader, and figure it out that way. Nobody on a forum is going to be able to help him.

See, you guys are throwing tire pressures out there, not realizing that "optimal" tire pressure depends on several things: ambient temperature, aggression level, elevation, etc.

He needs to get a laser temp reader, and figure it out that way. Nobody on a forum is going to be able to help him.

what we need is for the OP to let us know what kind of driving he is talking about here - daily street or track.

A laser temp reader is overkill for daily driving, but a great idea for the track. It would also address 98three28i's point - 36psi hot is low for daily driving, but has worked well for me at the track.

I ran 34/37 street, 31/33 track (cold)

Just wondering what would be the best pressure for my tires, I have a 2003 E46 M3 with the 18'' M wheels, with Contisport contact 2 tires

Considering the possible combinations of abient temperature in your location, road type, load in your car, your driving style, the numerous different tires you may choose, etc. Recommending an exact tire pressure for your car is near meaningless.

You can get a digital thermometer and learn how to use it. Or you can go the route racers used befor digital thermometers:

Get a bottle of white liquid shoe polish, the same stuff nurses use on their white shoes, with a built-in sponge applicator. You can find this at any drugstore or big box store, usually for less than $2.00, and one bottle will last a long time.

Put five polish "dots" in a line across your tread, from the inside edge to the outside edge. One in the middle, one on each side of that dot about half-way to the edge of the tire, and one on the inside and outside edges of the tire. The edge dots should be rolled around the curved tread on the edge of the tire.

Go driving. After a short drive (like one run if you are autocrossing), examine the wear of the dots. If the center dot is worn more than the outside dots, pressure is too high. If the outside dots are worn up the sides of the lips, pressure is too low. You get the picture.

It takes some practice and some playing with, especially since your tire pressures change as the tire heats up and as the ambient temperature changes. But you can learn to read the dots and get your tire pressures about as good as they get.

Having used this method for over 30 years, I'm more comfortable with it than a digital tire gauge and it's a whole lot cheaper. I'll put it up against a digital gauge any day.

Oh yeah. The dots wear off pretty quick, so you don't have to worry about people wondering why in the hell you put white dots on your tires.

Good Luck,
OldBMVGuy