Pontiac's Solstice roadster has now been marketed for four years, and sales are stagnating. But GM is counting on the introduction (later in 2009) of a coupe with retractable top panels to revive sales. It will be available as a GXP version only with turbo engine, and a choice of manual or automatic transmission. Besides the coupe, GM has brought several changes to the Solstice, such as standard antilock brakes with Stabilitrak and a limited slip differential.