This is exactly what I did. I bought my NSX with a Dinan chip already installed (It was in a socket in the ECU, not hard soldered), and I swapped it out for a Dali chip. While I can't compare the gains of the chip on the dyno (Dinan chip was dyno'd with stock 16" rims with 225's, Dali chip was dyno'd with 18" rims with 285's), the Air-fuel ratio of the Dali chip was much better, and the torque curve was smoother. I'll see if I can get my shop to send the graphs so I can post them up.
I really should throw the stock rims back on and see how much that affected the dyno readings...