I have not had a problem with the way I lock my converter, however my transmission is built and I have a 3200 Precision converter. But my friend TurboTimmer runs a stock D5 converter and runs it the same way. He has had no problems other that its hard to spool a large turbo against the foot brake with a stock D5 converter.
I don't know how much I gained by locking the converter, my car came around pretty quickly but I had changed several things all at once.
I run Hoosier 28X9 slicks on Weld 15X8 wheels with the stock 3.42 gears.
When I'm at home I can give you my complete combo, I have it on a word document.
If you plan on going any faster i think you need to upgrade your injectors IMHO.