I fitted mine after stage 1, the ECU should adapt to the extra air intake. Tbh I can see it being 2 things, either it's not fitted correctly or you're expectations are too high. Where are you based mate, if you are local I would be happy to have a look at yours and give you a demo of mine?
I don't think the DV will be an issue as even when mine had a half inch split in it, the intake still made a noise. If you are thinking of swapping DV's don't pay out for the Forge, go for the Rev D OE type, less than 60 quid from TPS.
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Not sure if this will help, its not the Evoms, but the sound is almost identical to mine, not sure about the engine noise though, sounds like a tractor.....
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