I haven't got personal experience with Team Xtreme, but I think this is not an issue with the company's goals and intentions. I think instead this may be a problem with the demand may be exceeding the capacity to handle such an amount of orders and calls for support (at least I'm surprised by how many kits there seem to be out there).
Most big companies offer their new cars in both mid and rear configuration by now... I think they need to be at the top of their game to justify paying 200GBP+ for a conversion when a standard car offers what huge gap the Vega covered a few years back.
I think their Gen 3 Vega has features that again are a step ahead of the big manufacturers, but it might be that this is causing the friction between quality from the car's design and overall product experience for the customer. The result I understand is very frustrating
