I can't imagine why it matters which is faster stock. There are probably only 3 of each with no mods. If you have to keep it stock the TTA is probably going to beat the Buick every time, if you can find a stock one to race. It has a slightly more efficient I/C, 2.5 more #s of boost and way less brick factor. But, if it's modified light to light and drag strip performance you're after the Buick is less expensive and is better equipped from the factory. More parts available such as headers, engine tie-down, motor mounts, wheels, roller rockers, and heads for that matter. Stretched I/Cs fit in both but are in danger of dragging on the ground in a TTA. The rear-end in the Buick is an 8.5 inch 10 bolt with 3.42 gears and drum brakes which will hold almost unlimited boost on the line while the TTA got a 7.5 inch 9 bolt rear-end with 3.27 gears and big discs which will hold about 4 PSI and disallow the use of many aluminum wheels. Some Buicks came W/O posi which is unfathomable. I know a guy who had one. It would burn that right tire for miles. Don't get me wrong, I love my TTA and have overcome many of the hurdles to make it a great drag racer and have not affected it's superior handling yet, but I've spent several extra $s trying to get it to get out of the hole as well as some of my buddies in their bricks.
If you need to get around corners in a hurry, the TTA is the obvious answer. I like corners. Sometimes I even show up at SCCA events and give 'er a whirl. Literally. Too much boost and tight turns = loop. I attribute 55# injectors to occasional stalling when getting in and out of boost rapidly. Also not good.
Other Buick ammenities: Seats 4 comfortably
Also holds their luggage
Or a set of sticky tires
Full frame
You can paint a T-type any color you like
Few people are aware of their capabilities
Insurance is reasonable
Can be made to hop several feet with hydraulics
TTA coolnesses: Collectable
Hatch area is useless for cargo, but unsurpassed for subwoofers
Even fewer people are aware of their capabilities
Chicks dig 'em
Real gauges
Nobody calls it a Monte Carlo
Easy to decide which color to buy
That's all I got.