I think my levelers are "Equalizer Systems" brand. www.equalizersystems.com
They seem like pretty good levelers. I use some blocks of micro-lam placed under the plates to keep them from wrecking the pavement so much, and it also gives me more lift height.
My son's got a heavily modded '99 Vette fixed roof coupe. He runs in NASA Super Touring 2 I think. He's got a 442ci LS motor, almost 700 crank shaft h/p normally aspirated. Tons of suspension and brakes and aero. He got the car running mid summer last summer so he's still learning it but he took it to Mid America for a practice day and beat up most everybody. I've got a '86 Vette coupe with a 383ci forged 10.5/1 mini-ram trick flow heads, moderate cam, big brakes and lots of suspension mods that I autocross and do some high speed solo NCCC (National Council of Corvette Clubs) and SCCA stuff, and open track HPDE stuff. My son also has an '87 Vette coupe that he gutted out and did big brakes, some suspension, and long tube headers with true dual 3" pipes, no cats. All our cars have 4 point roll bars (he's going to cage his '99 at some point). That '87 he runs 335/30/18 Hoosiers on all four corners. Looks like a steam roller. Sticks like glue. Weighs 2700lbs. He dynoed that and got 330 rear wheel torque so it does pretty well. He's a very good driver. 22 years old and he's been autocrossing since 2 days after his 16th birthday.
Here's some shots of his '99: Welcome to Facebook
Here's a few of his '87: Welcome to Facebook
Here's some random shots: Welcome to Facebook