Wayne, Im going to hold off any making any judgments about the capability of mods until I see one of the 172s which were at saturdays RR tested down at Power Engineering (Hint Hint Mike)
I have my doubts about the way each of the cars were tested, and feel that they didnt do repeatable testing (and I feel that this is held up by the fact that they didnt want to retest Mats car - only my opinion of course), (imho) a car should be given a few runs to make sure that everything is correct (oil heat even, distributed well etc)
I only comment on this because at PE (and Im would think at other rollers) they say they give the car a couple of runs before just to make sure that everything is correctly running (oil etc) in order to give a good, and repeatable, power run.
If anyone else with a 172 or cup is willing to do a power run at PE, give me a shout.
Chris, I would only take the figures you got from PE as the comparison of your mods, as you cant compare between rolling roads, but from my experience PEs results are repeatable (mine was down there in October) and when mine was down there on friday it still - instantly (after 2 warm ups and a power run) - pulled the same power as in october, so I take this as a good test of their rollers, NOT that Im saying they give the correct figures, because I dont think that they can give absolute figures (even at the wheels) but for comparisons it seems to be dead on.
(And just for info, I would love to be able to have an RR that I felt like I could trust close to home, doing a 200 mile round trip just for a power run aint great, but PE has my business for the mo)