You can break the tires loose in the bleach box at the dragstrip, ever drive on a day when the roads are wet? the tires still break loose, even on the factory convertor.
If you lock the hand brake it's easy to do burnouts in a bleach box, just be sure to jiggle the steering wheel back and forth a little, and leave it in drive, so it shifts to 2nd, drop the handbrake when you're done.
Dry roads are a different story, torque convertors with a higher stall let the motor rev higher before it locks, like holding the clutch in a little longer on a manual car.
Now, you need a valve body kit to shorten the shifts up, building valve body pressure will help it shift faster and harder, but you need to recalibrate the valve body to truly make it shift between gears quicker. Not as bigh a deal when in M mode, but this is partly why there's such a delay between the button press and an actual gear change.
One company prototyped a valve body kit, but it never went into production. A company such as level 10 can custom make one for you though.
One company makes some nice torque convertors for our cars:http://www.jmousa.com/us/flash/frame/index.html
And Phantom grip makes an LSD conversion kit for our tranny as well, it turns the factory diff into a limited slip unit.
TurboEast's IS300 ESK supposedly works too, but there's little info on that, let alone verification of compatibility, so I'd avoid it for the time being...