Stay clear of cheap exhaust systems - it'll be a pain in the arse to fit and will rot within a few years. I'd also question the performance gains.
If you're after more power you should save you cash and get the miltek challange kit with the flexipipe at the engine manifold. You should also sort out the induction at the same time..... not cheap, but should give you a noticable gain without the need for a re-map straight away
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Eco-warrior