http://www.kandn.com/dynocharts/69-6030.jpg

according to that its a 9.5 hp increase. but if you look closely, there is ~10 degrees temperature variance, would this have an effect on how much "power" was added?

Not sure how much 10 deg would effect actual numbers, but there would be some difference. Temperature of the air plays a big part in HP.

It would not if the power data were corrected for baro pressure, vapour pressure and air intake temperature (to SAE J 1349 for example).