XR-7 was just a trim package. I know the T-bird had the 'SC' supercharged model. I'm not aware of a Cougar version, but who knows? ...I always wanted to graft a 53 Studebaker front & rear sheetmetal on a Cougar, thought they would blend a lot better than the 49 Ford/Merc.
From Wikipedia:
"The Cougar entered its seventh generation with a completely new body and chassis. Nothing carried over from the previous Cougar except for badging and the engine. In fact, only six parts were carried over from 1988. The biggest change was the switch to the larger
MN12 chassis, which was shared with the
Ford Thunderbird. The chassis featured a fully independent rear suspension, a first for the Cougar. It was also nine inches (229 mm) longer (104.2 vs. 113 inches) for better rear leg room. The flowing lines and extreme notchback roofline were still there, but this generation integrated the two much more successfully. To the surprise of fans, the car had no V8 engine available when introduced. Instead, the base LS had a
naturally aspirated 140 hp (104 kW) 3.8-L V6, backed by a
four-speed automatic transmission, which had a hard time moving the nearly 3,800 lb (1,700 kg) Cougar."
"The
XR-7 had a 210 hp
supercharged version of the same engine the car could be equipped with a five-speed manual transmission or a four-speed automatic with overdrive. Mercury spared no expense in equipping its XR-7 performance model. Standard features included four-wheel
antilock disc brakes, an electronically adjustable, sport-tuned suspension, monochromatic paint scheme in red, white, or black, and 16-inch alloy wheels. The base LS's more luxury-oriented features included a fully digital instrument cluster and exterior chrome trim."
The 3.8 supercharged was replaced in 1991 by the 5.0 V8 so it was only used for 3 years. 1989, 1990, and early 1991 models.