Coilovers - Why keep the Torsion bars?

[owdlvr]

So I've spent the morning reading through as many of the coil-over threads as I can find, but what I can't find an explanation of is why you might want to keep the torsion bars when moving to coil-overs?

I do understand the issue of stressing the upper shock mount with the full load, but assuming one installs a 5-bar Kafer Bar, is there any reason to retain the torsion bars vs. a unibal or GWD bearing?

Ultimately I'm looking for a way to easily raise and lower the back end of my beetle for changing from a gravel rallyX setup to a road or track setup. Indexing spring plates each time is not a realistic solution.

-Dave