I know something about everything about these cars, depending on who asks and how much beer I drank before I answered.
1981-1989 or so saw nearly every Buick model with a "T-type" variant. I've personally only seen the Electra (PA), the LeSabre, and Regal. The Regal needs no introduction, you all know about the GN, GNX, and probably even know about the super rare 1989 Trans Am pace car deal. I think the only model to escape the T was the Reatta, probably because GM failed to deliver the RWD variant they developed...
What makes the BLT (Buick LeSabre T-type) special is that it's the only FWD H-body platform to race (and win) in Nascar. Something like 119 LeSabre "Grand National" models were produced in '86 to qualify the body for racing, for the explicit purpose of testing out a rear quarter window delete body panel. I think the most recognizable car was Bobby Allison's #22 with it's Miller graphics.
Notice the full interior?
Somewhere on the interwebs there is a photo of one of the LeSabre's leading a pack of G-body cars around a track. The '86-87 LeSabres were legit racecars, the T-type Lesabre was just a poor follow-up. I don't know if the #22 car was in fact a "flame red metallic" car, I'd like to think it was - my '86 LeSabre limited had that 1-year only paint, looked similar to the photos of the #22 car once you factor in UV fading over the years (also, c'mon, how many of these GM cars survived clear coat failure? That paint was special).
The T-type was special in that it was supposed to be Buick + Turbo, but FWD defeated that. The GN badges were special because they were *real* race cars - as far as I know, only the Regal and LeSabre actually raced.
The T-type is the predecessor to the SSEi and PA Ultra - if the FWD 440-t4 hadn't been such a shit basket all of the FWD 3800's would have been turbochargered from the factory and available to the public with a warranty. GM actually made a Turbo variant of the LG3 FWD motor (I think they planned to turbo the 3800 from the beginning with no N/A variants, explains the EGR and oversized EVAP stuff).
There isn't a car on the planet I love more than a BLT: it's the original 3800 car, a true grassroots racecar, a spiritual succession of the G-body (My opinion).
I have a 1987 BLT that I want to build a modern replica of the '86 BLGN/#22 car. Flame red metallic, sealed beam headlights and grille, turbo LG3 + 4t80.