Well Andrew you hit the nail on the head when you mentioned heat. Some of those put out soo much heat that it dries out the silicon seal between the glass lens and the light frame and the glass falls out and breaks. John Monzo has the ones that do not produce all that heat and all stays good. He is the president of the CAC and runs this site. email: email@example.com or 609-634-6518
Just got my 1990 and I'd like to change the headlight bulbs to something brighter. I've used SilverStars on another car. They worked OK, but wasn't happy with the price since I only got about a year out of them.
HID - I've seen plenty of conversion kits claiming to work with the Allante, but I haven't found anything I'd trust yet.
LED - Saw some on Amazon that were an exact fit and didn't need anything extra for conversion. Some of the bulbs had small fans in a heatsink while others only had the heatsink. What kind of heat can the headlight take without breaking or melting something.