Those are good mods for a turbo 350 or a 400. It really depends how hard ( and how often ) you are going to run it on the strip. I have a turbo 400 in 2 of my vehicles, both are running a shift kit and I have never had a problem with the trannys or the stock converters. I am running these behind big blocks, on the street only, I do run synthetic ATF in both units which speeds up the shift.
You might be thinking of running a converter with a higher stall so you can get a better launch, in which case the welded converter will be stronger and more reliable. I am not able to help you with who is the best manufacturor, because I am running a stock converter and haven't been following the latest trends. You will want to talk to someone who has experience with racing in the automatic classes. I would call one of the prominent makers and ask them for their advice. The reason is, because you will want to match the stall speed of the converter to the engine you are running. Be aware that increasing the stall speed on the converter will cost you gas mileage.
Bob
