Their is no dought that with the right converter you will be faster.,i ran around with 456 gears and a 4,500 converter with a auto,for 10years.,in the end i put 373 gears in which helped alot.,. i was not on boost but had a very healthy car.,you will love the track improvement., it will fly.,with boost i do think its a must having a auto.,one thing to add is that a turbo 400 with a converter is a heavy beast, nothing like your stick,you will need to go with a stought rear which im sure you probably allready done,i just think it will become a trailer queen in the end., seems that after all the hp, once you go auto it will be the next step., one thing is for sure and that is you can always switch back!