First modification I did to my truck. Went with the LMC conversion, gutted them, turned them into proper projector housings and went with a quality set of HID.
The other thing I did was change the wiring. Once upon a time, Iwas a teenager, and my first car was an '87 Superior Sovereign Landaulet on the RWD Cadillac chassis (which I kept forever, serving as my daily vehicle until I was 30 and bought this truck to use as a daily). Those Cadillacs had four headlamps up front as well. But unlike my '89 Suburban, they were wired in a better, smarter way. The outer pair of lamps acted as HI/LO, having a regular setting and a brighter HI setting, so switching on the HI beams would make those get brighter, while also turning the inside set of lights on. The most logical way to operate a system of quad headlamps. Same setup on my '67 GTO, '67 Chevelle, '72 Lincoln, '73 Oldsmobile etc.
Now, as a kid, I presumed all quad headlamps setups worked that way, but that's not the case. As such, I've wired every car I've ever owned that didn't, so it does. My '89 Suburban is no exception. LO has the outside set on, switching to HI makes them brighter and also switches on the inside set.