coil spring front

@HemiDenny produces the HDK coil over conversion, that's a good choice. He's a member here as well. HDK Front Suspension Parts For Mopars

There's also RMS with their AlterKation conversion, probably been going the longest and run by a lot of folks. Front Suspension

The QA1 suspension was based on Gerst's offering, which was really just a cheaper copy of the AlterKation. QA1 has no doubt fixed some of the issues that came up with the Gerst suspension, mostly broken welds on their uprights due to a less than great initial design.

Of course, there stands as always the question of what you're planning on doing with the car, because the torsion bar suspension with the proper upgrades can handle just as well, or better, than any of the coil over conversions. And for less money.