The original 'supercar in a suit' may be the BMW M5, but while Bavaria has long abandoned the performance version of the 5 Series wagon, Mercedes-AMG still makes a hardcore version of the E-Class longroof. With a 4.0-liter twin-turbo V8 producing as much as 603 horsepower and 627 lb-ft of torque, the Mercedes-AMG E63 S Wagon has more grunt than an Audi RS6 Avant, but what if that's not enough? What if you don't want to just beat the Audi driver but humiliate them? You could turn to Brabus and get up to 800 horses, or you could go with Renntech. The Florida-based tuner has what it calls the R3 Performance package, and as you'll see below, it makes any stock German luxury wagon look pathetic.

This package (for 2019 models forward) features lightweight forged billet turbo wheels with larger-than-stock impellers, as well as an increase in the turbine trim. If that sounds like gobbledygook to you, basically it means that it has bigger turbos with stronger and lighter wheels in them. Thanks to that, Renntech claims that there's no change in turbo lag despite a greater size. The wheel cartridge and its shaft are all CNC machined and reinforced, then flow tested to ensure quality. More than just greater power, Renntech says that the power curve improves between 5,500 rpm and 7,000 rpm, so you can enjoy revving it out for longer.

All in all, Renntech says that its turbos spool up quicker, offer a more responsive throttle, have a lighter rotating mass, and reduce back pressure - all for immediate power delivery. Best of all, these are bigger turbos that fit in the stock location and use the OEM oil and coolant lines too.

Along with the turbos, the package includes an ECU upgrade, stainless steel downpipes, upgraded CPC (computer powertrain control), blow-off valve adapters, special air filters, and a proprietary fueling upgrade. All of this results in up to 1,017 hp and 873 lb-ft of torque on 100 octane fuel and up to 965 hp and 817 lb-ft on 93 octane. If you're wondering what it costs, it won't be cheap - $29,380 before tax, but after the $112,450 cost of the base wagon.