My springs are the blue ones (just a bit lower than the Veloce ones, and a fair bit lower than standard). I would guess the red ones might be a bit unsuitable for UK roads.
Kevin at EBS did suggest that my original Veloce springs would work fine with the Bilsteins, but since HB had developed springs and dampers as a package, it seemed to make sense to go the whole hog. I was finally swayed by the (flawed) Autocar comments about them being a half-way-house.
Following on from above, I've had a good look through the interesting link you gave me. I can confirm that I'm on original 16" wheels with 205/55 R16 Continentals. I run them at a lowly 28psi to give a bit more compliance. Interestingly, before the HB convesrion, I fitted some Pirelli P6000s in an attempt to soften the ride. Sadly, because the tyre walls flexed more, the ride was actually worse, because the suspension, by not working so hard, was relying on the undamped tyre walls. Ironically therefore the overall effect was worse than before! (Plus they were as noisy as hell, and, I later learned, the speed rating was wrong!!!). The Contis are fairly quiet, last well, and give loads of lateral grip especially in the wet (but they're absolutely crap on ice/snow - or is it just the car?).
Incidentally, I borrowed a standard 147 1.6 the other day, and the ride was heavenly!
I don't want to unfairly knock the HB kit though. The car undoubtedly handles better than before - by some margin. It really inspires confidence when you're pushing on. I just shouldn't have expected the ride to be converted into that of an XJ6!
One last word on the ride height - the HB blue springs are supposed to be 15mm lower than standard, and the red ones lower still. Notwithstanding, my car is lower than it was (probably by 10-12mm from its original Sportpack/Veloce setup, which itself was lower than standard). I can't explain this - but there it is!!!
Geoff McAuley AROC