From the “Standard Catalog of Pontiac 1926-2002 2nd Edition” by John Gunnell and Ron Kowalke
“The new 1999 Grand Am coupe and sedan were introduced in the spring of 1998. Changes made after the 1999 model-year changeover included the addition of a GT-coupe and sedan with a 175-hp version of the 3.4-liter V-6 engine.”
“Pontiac’s total output of 1999 model U.S passenger cars was 629,938 (not including Montana vans or Canadian units). Pontiac had a 6.4 percent share of market.”
The Trans Sport name was changed to Montana in 1999. The Grand Prix model continued to tout “wide-track”. A convertible model was added to the Sunfire line.