In the latest edition of the Driven Media’s series exploring how to cheaply make a track day weapon, it has finally come time for its Subaru Impreza WRX Wagon’s weight loss regime.

The natural enemy of performance, weight is a snowball of worsening performance characteristics. A heavier car means you need bigger brakes, heavier duty components, and a bigger engine, all of which adds more weight and only makes the problem worse and worse.

So, naturally, the first effort of the backyard tuner should be to reduce the weight of their track day car. According to the team at Driven Media, there are three ways to do that. First, you can spend a lot of money on carbon fiber componentry and exotic lightweight materials. Alternatively, you could spend a reasonable sum on less exotic materials.

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The option they decide to go for, though, is the free one, which involves simply stripping the car of every single creature comfort. And they get to work, finishing with a car that is impressively bare.

The results are impressive. Starting out at a curb weight of 1,430 kg (3,154 lbs), by removing all of the seats (apart from the driver’s), the carpets, the head liners, and just about every soft material, the team manages to liberate the car of 135 kg (297 lbs). Following its efforts, the car winds up tipping the scales at 1,295 kg (2,854 lbs).

As their tame racing driver, Scott Mansell, points out, in Formula 1 teams suggest that every 10 kg (22 lbs) saved is worth around 0.3 seconds per lap, so by that logic, these upgrades should be worth around four seconds per lap.

Unfortunately, the test is ruined by the fact that it started raining before the team could set its second lap in the lightened car. However, the quality of this Impreza WRX as a track car is proven by the laps that Mansell ends up running in the rain.

Aided by its all-wheel-drive system and Mansell’s skill, the car manages to pass a Porsche 911 GT3 RS, a Ferrari 488 Pista, and a Radical track car. He admits that it’s hard to be certain how much the diet has improved the car given the conditions, but it’s even harder to argue with the joy that Mansell appears to be feeling from behind the steering wheel.