Andy I saw the same thing as you I think...You don't have to permenantly mod the radiator, but most commented that it is much easier to remove the fan(S) before the work...Then reinstall the blades after the header is in place...
Also on average a 2.0L north american protege looses about 30whp between the flywheel and pavement/rollers...the % loss changes a little with the mods made, but you still loose almost identically the same amount of bhp through the drivetrain...Depending on the type of dyno used, the base run numbers can be very different...On DynoJet dyno's I have seen average numbers around 101whp...I saw a base run on a P5 as high as 106whp on a DynoJet, but also one as low as 95whp...all I have seen were between those two extremes (on a DynoJet)...
But a few have used mustang dyno's as well as other types...the base runs on a Mustang Dyno were around 90whp from what I remember...
Either way it is irrelevant if you use the same dyno to compare the numbers and mods...That is what keeps it consistent and accurate...The overall numbers don't really mean much, but the gains you make usually hold equal when compared to another dyno results...