We tried 4 out, mk2 escort, smart car, tata nano, and stock Polo!
There's a few problems:
1) Wheel to ARB contact when on lock- solved with ~ ET0 wheels (which means stock Polo arches are a no-no)
2) Drop link to TCA/Compression Strut/drop link off strut body- Basically there's no room! Driveshaft limits drop linking above the tca/strut link, and ground clearance limits going below it.
3) Link ARB to strut (ala Salzmann) means disconnecting the ARB for every castor adjustment
4) Angle of ARB required to ft under the front frame bar, means you'd have to modify the inner arch on some cars
All in all- it's not a 'mass market' idea, or one that could easily be retro-fitted to current stage 3 frames. The answer lies in a stage 3 with modified mounts to accept ARB blocks under the front feet, and a custom ARB with drop links to the compression strut.
For serious track use, you really need coilovers to get a stiff enough spring, especially if you're going to be using slicks.