Despite its questionable styling details and gross proportions, Porsche’s Panamera has proven to be an irresistible target for Germany’s legion of aftermarket tuners.The latest speed-shop to fabricate its idea of what an ideal Panamera should be is respected Porsche tuner TechArt.From its base in Leonberg-Höfingen, TechArt has now released the final specification for its GrandGT Panamera package.Widebody PanameraAs an exterior design exercise the GrandGT essentially turns Porsche’s Panamera into a widebody autobahn stalker. Elaborately flared fenders accommodate the GrandGT’s more generous tracking widths of 21mm up front and 42mm at the rear. Massive 22-inch alloys roll in the wheelarches. Aerodynamic details for the new styling package include a remoulded front bumper (featuring an integrated splitter), ornate hatchback spoiler and rear diffuser with matching air opening above - in the aft apron. TechArt designers have replaced the series production Panamera bonnet with a carbon-fibre item too, appropriately sporting two louvre cut-outs to channel the required supply of cooling airflow to the 4.8l V8 engine.Plug-and-play power boostAlthough the standard Panamera Turbo is by no means a slow car, TechArt’s engine technicians have managed to extract an additional 58 units of power and 130Nm of torque from the 4.8l turbocharged V8. By simply recalibrating the engine management software and adding its own custom-made exhaust system, TechArt manages to coax 426kW from the Panamera V8 without touching any engine internals or porting the cylinder heads. The performance gains courtesy of TechArt’s GrandGT package effectively turn the Panamera Turbo into an autobahn bound four-seater jet. To this end TechArt’s added some neat touches to the GrandGT’s cabin. Adding fold-away tables for the rear passengers and 12V power points, TechArt's enabled passengers to work on portable devices seamlessly whilst the GrandGT driver explores its 315km/h top speed potential...One of the better Panamera aftermarket conversions yet, TechArt’s GrandGT package will make its public debut at the Zürich auto show during the second week of November.