The stock converter's fine. With anything higher, you're going to need 12 inch slicks on the back. The stock turbo already spools like right now anyhow. With a stock turbo and ported elbow with dump, my 275 drag radials were worthless. I mean worthless. Why would you want a converter that runs hotter, and is looser up top? He's not trying to compensate for, or trying to gain back some power or speed he lost down low. I'd invest in an A. scanmaster B. boost gauge, C. oil pressure gauge D. rear seat braces, and E. a good set of tires. Though I wouldn't try to continually push low 12's on stock injectors. Screw that. If you have your heart set on injectors, just do the 60 pound mototrons. There's zero point in staying 'stockish' because there isn't such thing as 'stockish'; it's either stock or it's not. If it's not stock, then don't shortchange yourself and go for some lame 36 or 42 pounders. Just go for the gusto. The mototrons are relatively cheap, easy to tune with, and have a good spray pattern. They're efficient and quick. And if you ever dump the "all I wanted was 12's" (yea. that's what we all wanted too. now look at us.) malarky you'll already have the good injectors present.
I've had a decent combo on a stock drivetrain and the car sucked balls. It was like driving on an ice rink. Get a good sway bar and new bushings all the way around. Check your shocks and springs too, to see if they don't suck too much as they sit now. With what you got now, you already have the potential of going pretty quick as it sits. Don't have the cracks start to form by your B pillars on the roof by not putting in all the required braces. I'd also look at a good set of brake pads too if you already haven't.
And for us to give you some good advice, put your entire description down in the signature so we know what you already have, to include any exhaust mods, suspension mods, anything.