No not really mate the tone doesnt change, Might have something to do with the maf seating... Perhaps its leaking around its fitting slightly... ( Will try some silicone seal ) Bit disappointed by the drop in power more than anything. I've ruled out dv... And done the PCV test, and also had the PCV off whilst doing my cam follower today... To check for sure...grumble,grumble.
I'll whack in some nology plugs and the rev g dv, and retest, although I'm almost certain it won't make any difference.