Which is the best high-performance SUV (that isn't a Lamborghini)? Is it the Aston Martin DBX 707, or the Porsche Cayenne Turbo GT? Well, it's time to find out! Mat's got his hands on these two SUV powerhouses to find out which is the must-own performance SUV! So let's see how they compare. Starting with the Porsche, it's powered by a 4-litre twin-turbo V8 640hp (90hp MORE than the standard Cayenne Turbo) and 850Nm of torque. It's equipped with four-wheel drive, and it costs from £150,000. Think that's expensive? Well, you'll need to spend more on the DBX 707, which starts from £190,000! So it's up on price, but it's also up on power! With a Mercedes-AMG 4-litre twin-turbo V8 under the bonnet, coupled with a pair of turbos taken from the AMG GT Black Series, it can produce 707hp and 900Nm! When it comes to exterior design, both have upgraded over the standard variations of each car. With the Aston, you'll find a more aggressive front end coupled with a bigger grille, along with sporty side skirts and a large diffuser around the back. With the Porsche, you've got a carbon fibre roof, bigger air intakes up front, and a carbon fibre diffuser which comes as standard. On the inside, both cars are just oozing quality. In the Porsche, you'll find Alcantara throughout the cabin, a pair of super comfortable sports seats up front, and a well-laid-out dashboard and centre console. The DBX 707 is certainly more colourful than the Porsche and the entire cabin is covered in soft-touch materials, but the button layout and design isn't as clean as in the Turbo GT. So which would you choose - the Porsche or the Aston? If you're undecided, then you know what you need to do - stick with Mat for this all-new group test review!