1/4 mile times

Pay for a good chassis dyno tune,

Set up a Cal-trac suspension set up, for the price they are WELL worth it and you'll never look back.

Sub frame connectors.... always a great idea.

It's just money right? :-D

That car should be running an easy low 12, if not high 11 IMHO.

That converter should be fine with that set up. I wouldn't do a fuel cell either. Sounds like you got "good" parts to make a quick car, but your set up is waayyyy far off. And 4:10's should work great as well.