Standard GRiSO VS SE

Hello there learnered friends and fiends, got a question after and observation today.

Two friends came over today, one with a 2007 1200 GRiSO and the other with 2008 and together with my 2012 SE, we toddled off for a ride through the smoke hazed twisties.
One the way back we swapped bikes a couple of times.
Boz has a 2007 with 7200~kms on the clock, Dan has the 2008 with 45000km on the clock and my 2012 has 33000km. All are rollerized, all run same map, Boz has termi pipe, Dan a zard, and I have a custom twin outlet and crossover. No snorkel. All recently serviced and tappets done.
First observation is Bozs GRiSO runs pretty much perfect with the map, mine coughs and farts a bit from 3000~4000rpm. Better than when I had a termi. Dan's is basically same as Bozs, almost perfect.
2nd observation is that my GRiSO feels at least 10hp stronger everywhere.
Are the models different somewhere in the engine?
Anyone else found this before?

If they are rollerised, no. The engines are identical.

Were there different offerings in Oz?

In the US, if I have this correct...

2007-2008 GRiSO - 1100, mag wheels
2009 GRiSO 8V - 1200, flat tappets, mag wheels
2010-2012(.5) GRiSO 8V SE - 1200, flat tappets, spoke wheels
2012(.5)-up GRiSO 8V SE - 1200, roller tappets, spoke wheels

The 1200's were a 2008 MY model here, we only got the 1100 for 2006-7.

When talking about the motor alone all the flat tappet Grisos had the same cam profile, the part# changed at some point, I can't remember exactly when, but that was because the shaft itself was machined differently to allow the use of shims to minimise end float and reduce noise. The early, pre-shim, camboxes were hellaciously noisy! Believe me, I owned one! I know!

The big change was of course with the change to roller tappets which simply because of the way they work require a radically different cam profile but how this actually translates into valve movement is another matter. It obviously can't be too different because there were no further factory map updates after the -03 version that was used from, I think, mid 2010 right through to the end of production in 2016/17.

In reality, apart from cosmetics and cycle parts all 8V's are very similar in the bits that count, cam profile, port sizing, combustion chamber shape, piston design etc. There were changes made to the cambox castings and weirs when the changeover from the earlier 'Long plug tube' setup to the later 'Short tube' type appeared in late 2011 but I'm not certain if there were any changes to the actual head castings, I believe not.

Hi Pete, are there head gaskets in different thicknesses?
Apologies if I've got my wires crossed with some other model/brand.

Yes there are but that is not model dependent, the different gaskets are used to set the squish and the purpose is to lower oxides of nitrogen. You match the gasket to the cylinder height. In performance terms, (And in my opinion any real quantifiable terms with a small run motor like the 8V) the difference is negligible unless you set the squish too tight in which case it makes all the difference!

What about noise in general?
I think the 8V valve train is very noisy, louder than the old enignes.
I even have the impression that my rollerized A8 engine is even a bit more noisy than before.

It's a very noisy motor, no question.