New LS1 Owners - Newbie Tech - What exactly is a Stall Converter?

I just recently bought a 98 Z28 A4 and I have heard a lot about stall converters. What exactly does a stall converter do? How would I go about installing one? My car is an everyday driver, does a stall converter make city driving a hassle? Is a stall converter harder on my tranny? Any other info about stall converters, a newbie like myself should know would be great. What is a good converter for a 400 hp setup? I am looking to upgrade with heads and a cam! :drive:

Read this link it should help out http://auto.howstuffworks.com/torque-converter.htm. I know they help out a Auto car's 1/4 mile time alot.

Read this link it should help out http://auto.howstuffworks.com/torque-converter.htm. I know they help out a Auto car's 1/4 mile time alot.
That link should sum it up. They help you launch by getting the RPMS up to the stall speed.