Yes, Tischer and TurnerMotorSports both have the OEM water pump... as far as i know, there is no aftermarket water pump as of yet (it took nearly 6 years for an aftermarket [full aluminum] model came out for the E46 bmws - these supposedly last for 120,000mi+ i forget the brand though. :/
Here are the links to the ebay listings for the parts i used (and are working flawlessly so far)
Ebay:
Water Pump $356.00 w/ free shipping
Ebay:
Thermostat $68.39 w/ free shipping
Other parts/tools you may need for the swap:
Ebay:
TORX bit "E" $12.69 w/ free shipping
For those of you who have coolant overflow and spew everywhere, it has most likely gotten all over your cabin filter:
Ebay:
New E90 Cabin filter $18.57 w/ free shipping
Additional expenses:
Coolant w/ SILICATE
Drip bucket
Distilled Water
If you follow my DIY, you can easily navigate your way through the repair yourself and save you hundreds in labor costs. It's a pain in the ass and a messy process, but it's pretty straight foward. You'll have a few laughs watching my video anyway ^__^