Like supradjza80 said, the brake may be pretty far infront of the gas, but it's still relatively easy to do in a MkIII. However, you have to actually be ON the brakes to really get a good grip on the brake pedal and still be able to modulate the throttle (i.e. push the brake to make it closer the gas)... this presents some difficulties in coming to a real slow stop, lol. I do practice heel/toe as often as possible, but because of this quirk of the Supra, it's hard to do a nice slow decel and heel/toe down through the gears. Problem is that if you're not hard enough on the brakes, the ball of your foot may slip off the brake when you reach for the gas with the right edge of your right shoe... obviously this could be a fatal mistake, so be cautious and get plenty of practice when it's safe. Drilled pedals with studs would be a nice upgrade... ain't no slipping off that! Obviously this flaw isn't a problem on a track, as that you're burying the brakes for all they're worth when you're using them; not slowing down for soccer moms on their cell phones.
Unless you're doddling down the highway, you never want to shift gears in a corner while driving at the extremes of traction (like on a winter road... or a racetrack). A shift (down or up) could easily make the car swap ends just by pushing in the clutch (before the gear is even changed and power is back on). If the power applied to the backwheels to maintain speed through the corner was keeping the car balanced, pressing the clutch in will cause weight to shift off the back wheels to the front wheels... possibly causing the rear to slide. Note: If the tires are starting to squeal in the corner before you decide to shift, pray to whatever god you believe in when you push the clutch, 'cuz you're goin' for a ride! Obviously putting the power back on after the shift, if you made it through depressing the clutch of course, is just as perilous... There's dozens of other things to be doing while taking a corner, shifting isn't one of them. Do all the braking and shifting before you turn!
The reason a driver does heel/toe shifting is so that s/he can brake and change gears at the same time. Going from 120mph down to 60mph for a turn will require you to drop several gears to stay in your power band, carry your speed through the corner, and then come out of the corner under acceleration on exit... you don't want to brake, shift, brake, shift, then brake some more to get down from 5th to 3rd gear and drop the speed in preparation for the turn-in; you'll want to brake while shifting down and be ready to hold speed to the apex then accelerate. Heel/toe is really the only way to do it without causing undo wear on a transmission (or blowing it all over the track, slush box anyone?). Yeah, you can shift without using the clutch if you're pro, but one mistake at high RPM/high speed and the dog teeth are going to be DONE... just 'cuz you can doesn't mean you should...
