I knew there was a reason I went for a 3.0/3.2

Seems OK, TBH, the lack of cc shows at motorway speeds, and is evident in your vid. The bigger engines just keep pulling through.
My old 2.5, Goldie, had 3.0l cams and a Superchips chip, and was absolutely nowhere near my 3.0l MV6. It was shortlived, I overcooked it up the M40 one day when I was late for an ABS meet, much to the amusement of the ABS members as I pull in the carpark by coasting, and even more amusement when Tunnie had to come and tow me home

Also having never driven a 3.0/3.2 i value your opinion 
I've had both a 2.5 & a 3 litre Dan, and the 3 litre is very noticeably different in the pulling stakes.
If (or maybe when) I decide to have another Omega I'll definately be looking towards a 3.0/3.2, although I'd still be just as happy with a 2.5 if it's the right one (eg, very clean & minimum CDX spec)
As far as your video goes, your 2.5 is definately quicker than our's was without a doubt.
It will be interesting to know what it's done to the fuel consumption compared to the stock ECU, you'll have to post back and let us know once you've driven it for a while as you normally would.