Nice!!!
Going from memory here, I believe a 13.85 @ 99 was run with a Silver light weight '86 T-Type from Car's Illustrated Oct '86 issue Vol 4, No 5. The "From Buick with Balls" article.
You can view the entire article here. Article is at the bottom of the page.
Buick Horsepower
Then the April '86 Car & Driver article, they ran the 13.9 pass with an '86 GN. That 14.7 @ 95 by MT, was a rode hard and put up wet '87 Fleet car that they tested in CA in not so good conditions. I remember those articles like they were yesterday. Think I actually still have the copies around somewhere.
FWIW, here are two links that lists some of the major magazines these cars have been in over the years.
The Grand National / T-Type / Turbo Regal Buick Media Index
Buick Related Literature
These articles served two functions back then,
#1 Cold weather was definitely turbo weather, and they hated the heat.
#2 Factory stock 215/65/15 Goodyear Eagle GT tires sucked very badly when the temps were cold and the cars made an extra 75 or so hp. My friends original Eagle GT's lasted him 12k miles on his stock car back in '88 before he had to switch. Bald GT's in the rain definitely made things interesting.
I'll have to go pick up a copy of this one for sure.
Thanks for the heads up.
Patrick