Mercedes-AMG's GT 4-door Coupé is priced from £121,350 in the UK, with deliveries starting in spring 2019. By comparison, the Porsche Panamera Turbo starts from £115,100, but has 542bhp - 34bhp down on the 577bhp entry-level Mercedes-AMG.
The 630bhp GT 63 S variant is aligned more with the plug-in Panamera Turbo S E Hybrid, at £135,550 to the Porsche's £137,140. It's less powerful than the 671bhp Panamera plug-in, though.
The GT 4-door Coupé, which made its UK debut at the Goodwood Festival of Speed, is avaiable to order, with a range-topping, £148,950 Edition 1 offered for 12 months only. First customer deliveries aren't until early 2019, though. This short-lived top model will use the same 630bhp twin-turbocharged 4.0-litre V8 petrol engine as the top-of-the-line GT63 S 4Matic+. It is capable of propelling the car to 62mph from rest in just 3.2sec and on to a top speed of 196mph.
Lesser models can be equipped with the £3,600 Premium Plus package, which adds massaging multicontour seats, a head-up display, soft door close and other comfort options, while £3695 equips the GT 63 with individual rear seats and a raft of extras for rear-seat passengers including a rear touchscreen infotainment system and wireless smartphone charging.
AMG's Porsche Panamera rival will reach customers during the first quarter of 2019. Official pricing has yet to be revealed but a starting price of about £85,000 is likely for the normal car, with the Edition 1 to be priced well above that.