AHH, someone knows their Buicks. Its a 1987 WE4 Turbo-T. I usually just say Grand National rather than writing a novel trying to explain what a WE4 is LOL. The only diff is, the WE4 had grey interior, aluminum bumper supports, aluminum rear drums and the T wheels making it much lighter than the GN. They were only made in 1987 and only 1547 where ever made. Here are a few links with info about the WE4 Turbo-T.
http://www.hemmings.com/mus/stories/2006/12/01/hmn_buyers_guide1.html
http://www.g-body.org/history/b/over-b.php
Here are a few quotes
From the sales brochure: "The WE4 Turbo 'T' Package will enable you to merchandise a car that is similar in appearance, and yet lighter in weight, than today's Grand National. This reduction in weight theoretically makes the Turbo T faster than a Grand National, and for a lower price." I think the price difference was like $138, so not much savings there.
From hemmings muscle machines: A grand total of 1,547 WE4 Turbo-T units left the assembly line, meaning that aside from the GNX, the Turbo-T is one of the rarest turbo Regals to leave the line. The announcement of the model came compliments of a Buick Product bulletin dated November 11, 1986; already well into the model-year production, with a production start date of December 8. Interestingly, just two days prior, a bulletin had been released stating that the WE4 would no longer be available with the WO2 black-out kit trim package.
According to Dennis Kirban's book, Kirban's Guide to 1986 & 1987 Buick Turbo Regals, "They (Buick) did this so it would not be confusing having two Turbo Regals available at the same time in black." He goes on to explain, "The only difference between the new WE4 version and the black one with the WO2 exterior sport package would be the old WE4 version would have matching black bumpers. The new one would have chrome bumpers." Just how many truly black WE4s Buick made before the change is not known, but it's a good bet that not too many of these were built.