Modifying an EV for improved performance (power and handling, not efficiency) isn't a common thing, yet. That's mostly because EVs still aren't nearly as popular as ICE vehicles and they're limited on how you can modify them.
That's one reason why some find EVs boring because you can't add turbochargers, exhaust systems, intake systems, or any other fun go-fast parts. But you don't really need to. Powerful EVs are already fast enough and even if a tuning company is able to increase power, it won't be by much. Unless you're running your EV at a drag strip, modifying an EV is all about improving handling, increasing braking power, and reducing weight (and looks, of course). And that's exactly what Unplugged Performance did.
Matt Farah, a very popular automotive enthusiast and YouTuber, did a video for Hagerty's YouTube channel. He drove the Unplugged Performance Ascension R, a highly modified Tesla Model 3 Performance. Tesla owners can buy the full package or just parts of it. A full list of modifications wasn't provided but Matt says they modified the entire chassis of the car, "everything that bolts to the subframe."
From what I can tell in the video, the package comes with much larger front and rear differential coolers, large Brembo calipers and rotors, adjustable rear camber and tow arms, adjustable front camber arms, three-way adjustable coilovers (designed for the heavyweight of Teslas), lightweight wheels (saves 8 pounds a wheel), and other parts they didn't mention like stiffer bushings. They also widened the front of the Model 3 in order to fit very wide 315 tires (same size in the back).
So what did Matt think of the Unplugged Performance Ascension R? He loved it. He felt the modifications gave the Tesla better body control, more grip, and better steering. He said the EV felt more "energetic," "dynamic," and "hunkered down." He also said the NVH (noise, vibration, and harshness) was great, something some modified EVs have a problem with.
When he spoke to a representative from Unplugged Performance he mentioned that many Tesla owners used to drive powerful premium cars before and want to modify their Tesla. He mentioned that charging EVs is an issue on track days but soon more tracks, like Buttonwillow, will have charging stations.