Yes I do have a spoiler, but it always opened fully for three years until recently. Lexus Norwich think they may have been supplied with the non-spoiler springs, boxed as spoiler springs. During many years as an engineer, designing and building racing cars, I have always felt that the Japanese cannot make spring steel, brilliant though they be in every other way. My old springs simply got tired, and gave up the ghost quite suddenly.
I think it is essential that the boot opens fully, as when you are lugging several bags of shopping, it is a real pain to try and open the lid with your elbow.
davkel