Bringing back another old thread... Yet again...
Those cheap eBay chips are nothing more than a plastic box with a couple of resistors in it to try and "trick" the ECU into seeing a colder air charge coming into the engine (it changes the resistance reading coming from the MAP sensor to the ECU), thus adding more fuel to the mixture. Kind of like the difference of driving in the middle of the summer vs driving in the middle of the winter. The cooler, denser air gives the engine a little more perk because there's more air available per given volume, hence more fuel for the more air, hence slightly added power on those cool/cold days.
Those eBay schmucks figure more fuel should produce more power. The problem is, they're little "chips" are making the ECU add more fuel to the mix, but there's NOT the proper ratio of air there to support it and make it add power, so all they're doing is making your car run rich, wasting fuel. Luckily, ECU's these days sense this kind of BS after a few hours/days of driving and automatically adjust the fuel curve back to normal, completely ignoring that stupid chip you installed.
As far as power is concerned with our little Cube's, sure they could use a little more, but they aren't bad either. When matched with the 6-speed manual, the Cube is every bit as quick (actually a tad quicker) than my old '02 Miata 5-speed. There's a sign a little ways down from the entrance of my neighborhood. If I floor it right out of the neighborhood to that sign, I consistently hit 70 mph in the Cube. In the Miata, I could only manage 62 mph. Highway acceleration is equally impressive and also better than the Miata. I'm able to surprise quite a few people on the highway when I go to pass them. ;D
Of course, I do wish the throttle response of the Cube was better. It kind of sucks to throw it down into 4th or 3rd, floor it and wait a brief second for the power to come on. But once it does, it pulls pretty darn good!