looking for figures in mid 300's. spoke to r tech and he was very much against me using the forge bits but how much difference will there actually be in terms of power compared to other bits available like I know a revo induction and peron intercooler will be best for figures from research but can the forge stuff I currently have really be that restrictive and will the figures be way off what they would be with revo and peron?
I think with the twintercooler, it's extra volume for the turbo to fill, so can be a fair bit of pressure drop there.
How about a MK6 R intercooler for around £250 from the dealer? OEM quality, bolts right in, cheap and there's proven gains which reduces intake temps on sustained high rpm pulls, so perfect for a KO4 engine.
Add to that a 3" downpipe (which usually stays 3" to half way under the car before joining the OEM system) and see where that takes you.
After that you can add an intake and cat back if you want more.
Just the DP and intercooler + software should take you to 330-340ish.
It's highly likely you will need a HPFP to sustain that kind of torque though. Loba is arguably the best, but also the most expensive.