TTT for ya Phil. Gains are somewhat irrelevant when it comes to a tweecer in my opinion. Its a device to tune and get the car running the way you want it too. You can use a desktop but I think it would be easir with a laptop. That way you can datalog while driving down the raod and tune the car in real world conditions and not on a dyno.
Plus you can retune your car whenever you want and not have to pay dyno fee's.
for this reason alone is why im getting a tweecer. if i get any other benefit out of it then thats just sweet. you will need to get the r/t tweecer for the datalogging and thats about 550 shipped new. im sure you saw my post already but just passin info on