DAVEH50Z

So I am a complete fresher to the 350 world. I got my car a week ago and it's the best decision I have ever made. Just wanted some opinions on the upgrades it had already in it when I got it from the garage. And in general if there are better options. So the previous owner took it regularly to abbey motorsports and from what I see they are a linked trader on here and well known. They installed a PS revolution dual exit cat back exhaust but I'm unsure on brand. Cost around (£830). I'm wondering what decat pipes would be ideal or if there is a "better" system available? They also installed an AEM short take polished induction kit. Now this to me sounds awesome in motion, but I have heard a lot about the pop charger? Is this a better kit or would I not really notice? Any help or opinions appreciated Thanks David