You can try some wide open throttle runs to see if it revs higher before shifting. Or see if it'll go faster then the limiter.
You can also check if the torque management was altered. when mine was stock I could hold the brake and gas pedals to the floor in drive and it wouldnt rev more than 1800rpms now if I do it it'll go considerably higher before limiting.
As for installing it that's easy. You just pull some clips out with your fingers and the module comes right out. New one snaps right in, the plugs have a lever that locks and unlocks it. Really the only tool you need is a 10mm wrench to disconnect the battery.