Hey. I just wanted to give a little write up on my stage 1 upgrade to my bike. After doing a SE air intake stage 1 and a set of the older SE II slip on's ,I figured I would have to see what would be better for me in my current set up. I decided to NOT do the stage 1 ecm download via Harley anf not get a fuel manager but decided to just do the Xied plug ins. I really saw a big improvement verses not having them in. I don't have any hard data to prove this but to be honest , its an 883 motor and if I was looking for real speed I would have opted for a bigger motor/bike. I saw a big improvement in the idle after warm up vs not having them and getting rough idle. It was as if the ecm was having a tough time trying to auto adjust the AFR. Idle was not steady at all and was worst than the all stock (virgin) set up. With them installed, it was a more even idle and not too much over adjustment. Just by the sound of it I could tell the difference. As for performance, there is a slight increase in throttle response and take offs made me feel it was a different bike. I am a pretty big dude and this sporty had no prob hauling by butt! All in all I am not going to beat a dead horse on the debate of weather to use Xied vs fuel pak vs whatever. For me this works and am very happy with my setup. Thanks for reading and hope this helps someone's decision on there setup.