I would definitely be looking at IAT on the track. What you see in street driving is very much different -- the car has ample time to cool since you simply cannot spend as much time at high rpm in such a short period on the street without getting arrested. Borrow an infrared gun next time and shoot the blower immediately after a track session. Compare that to a street reading. The blower heatsoaks also.
You might try water injection. It is mechanical intercooling. The major car manufacturers tested it years ago and found it effective but never implemented it because they could not rely on the owners to keep the tanks full. The disadvantage over intercooling is that water injection cools the air only under load when the water is flowing while the intercooler cools all the air all the time. Both is best, in my opinion. I recommend the Aquamist kits. Vishnu Tuning did a little testing on a supercharged car and the results were posted in one of the Vishnu threads here. That car may already have been intercooled, though.