I paid £80 for my cupra ones, ceramic bases, silicone wires, tiny slim line balasts etc. frigging awesum and never had any issues! I bought the over day some £20 ones for my daily driver, just arrived in a simple polystryene box, and thats it! not fancy or instructions or fitting kit. Fitted them as ive done it loads of times before - worked fine. driving along and turned the lights on, speedo died and ABS light flicked on, seconds later light out and speedo back. Since then it doesnt do that any more.
Massive difference in the quality of the two kits, and i dono if the cheap ones will get too hot etc etc. Cupra I tend to throw money at, but the daily is just bare needs. lol!