As has been said it all depends on what type of machine they use.The older style ones usually hang off the tyre and you need to check the backs and take some readings then swap the guages round to the front so with a lowered nova they are unsuitable.
The newer machines use targets on the wheels that clamp onto the actual rim so you have no problems with lowered cars etc(well...only if it wont get on the ramp!)and they also are digital and you normally get a before and after print out showing camber,caster and toe.
The places in this link have the newer machines and iirc theres a printable £5 discount voucher on the website: www.alignmycar.co.uk
Plus with getting a printout your not just taking someones word for it that its set as it should be.
