i have done the modded inlet, basically 3" tube direct from the vec C larger scoop, straight into the lower half of the airbox which was heavily modded to accept this, then ported all the top side through to the TB, i tend to use standard filters replaced regularly as not a fan of performance filters.
i have really been toying with what to do about the exhaust, i worry that 2.5" is just too much and will sacrifice low RPM tractibilty for sake of a few BHP high up the rev range which is not what this engine / ecu combo seems to be geared towards. ideally i would like to compare 2" / 2.25" and 2.5" in various different tests to see which is the best all rounder, have to say i was shocked when i notice the OE system went down to 1.75" at some points maybe a little less.
im rapidly approaching the point between there being an inverse ratio between time and money spent against increased performance output, law of deminishing returns and all that.
