I recently decided to update the reversing lamps and also the licence plate lights on my 66 plate A3 Sportback with brighter LED units. Whilst there were many bulb replacements, all from China I couldn't find them with positive to the barrel of the H6W base. This is necessary because of the way the lamp holder is designed - whilst the tail and rear fog bulbs are negative "earth" the connections are reversed on the reversing bulb socket. After a detailed search I came across LedPerf in France who offered a bulb with correct polarity & built in resistor to fool the OBD and not produce a "lamp out" message on the dashboard. At the same time as I was ordering these I noted they offered replacement licence plate units specifically for 8V models. I thought that replacing them with brighter whiter units would also help when reversing. To cut a long story short when they goods came, the reversing bulbs were great and fitted perfectly and are much brighter. The licence plate lights were totally wrong, obviously for another model as resistors were also supplied on flyleads (so these were for a car with standard bulbs, not like the 8V which already has LED units. Getting LedPerf to agree to a return with them paying postage was a nightmare - some 26 messages back & forth! In the end I gave up as I didn't trust them to sort it out or refund postage. I had realised that I could use the lamp units they had sent by changing the connectors on the car with simple adaptors. Asking Ledperf to at least pay for the adapters was pointless, they just point blank refused.
If you do buy from them be aware that if things go wrong, it's virtually impossible to get them to sort it quickly and easily.