I installed a Fuddle Racing Converter several months ago and couldn't be happier with the product, the service, the warranty, the price, etc. All three models they offer are lock-up converters, so you retain decent fuel economy on the freeway.
http://www.fuddleracing.com/05stang.html#AODe
I initially looked at TCI and some other brands I'd never heard of, but they are all so outrageously expensive! I've used Art Carr converters in the past and they were always a good value (probably still are), but they don't yet make a converter for the 5R55S. Then I was referred to Fuddle Racing at some of the other forums out there. After doing some research and talking to people who already use their products, I made my purchase.
I would recommend the 3000-3200 rpm TC for most street cars. I chose the 3400-3600 rpm TC for my car, as I run mine at the drag strip as often as I can. The 3800-4000 sounds a bit too extreme unless the car is mostly a weekend warrior.
Worth noting: the rated flash speeds are for a stock car. The more you mod your car, the higher your motor will push the converter's flash point. For example, my converter now flashes to about 4300 rpm's with just JLT CAI & Tune plus 4.10 gears. 4300 rpm's is about where peak torque occurs, so my TC is perfect for drag racing now.
Some key benefits to a big stall speed: 1) at wide open throttle (WOT) you are instantly at high rpm (like slipping a clutch in manual trans), 2) at WOT during shifts, the engine never drops below the stall speed so there's no lag or bog from an rpm drop like in a manual trans, 3) launches are much more aggressive - even better than a manual trans, IMO.
At the drag strip with the factory TC and drag radials (D/R's), I was posting 60' times in the 2.10 to 2.20 range, which is about where most guys with GT automatics are running. With the Fuddle Racing Converter I now very consistently post 60' times in the 1.83-1.89 range, so I've netted about a .25 to .30 improvement!!! My 330' times dropped from the 5.70's down to the 5.40's. My 1/8 mile times dropped from the 8.70's to the 8.40's.
Driving around town is such a blast now! The car is always in the sweet spot for power. Just a simple touch of the throttle and the converter flashes instantly. Even if you don't floor it to cause a downshift, there is instant power on hand!
Great bang for the buck! $560 regardless of which stall speed you pick. I paid about $250 for installation. So, for about $800 I improved about 3 tenths of a second at the track!
