Are you going to the University of Illinois? I'm from Illinois, right near Peoria
Keep it up, I've found that hills are pretty important to get that mpg up above what your cruising mpg is. A recent trip to SC, thru gentle hills produced lower mpg than the trip thru PA and the big hills. Either way 50+ mpg highway is pretty nice
I've also found that a HAI for the ZX2 will provide some good results, possibly why my mpg is a bit better than yours. With IAT's around 110 I was getting 45mpg at 50mph and a 21 TPS. With IAT's around 140, at 50mph and a 21 TPS I was getting 55mpg, both while cruising in similar terrian. Makes me wonder what the upper limit for IAT temps are?