Multiple ?s Header, Trans, & axle

[wolly6973]

2 weeks ago I was installing my new suspension and saw that one of the CV boots was torn. I have no idea how old the axles were or how long it had been torn so I went ahead and replaced the axle. After that I noticed that the car pulls hard left on acceleration. Put it up on jackstands and the right side barely even moves. I wiggled the axle and looked at it and everything looked all right. I turned it with my hand and there was some resistance. It made the left side tire turn the opposite way from the right. Is that normal?
Did I mess something up with the new axle? It's got lifeteime warranty so should I try and replace it?
I did get an alignment afterwards so it should be good.

Also noticed that while the car is in neutral the left tire was still spinning. I hit the brakes, and it started to go again. Should that be happening?

Installed a Megan Racing 4-2-1 header today. When I was reading about headers everyone talks about making sure to reattach the mounting brackets. This header doesn't have any way of attaching. Will it be OK?

Sorry for all the ?s at once and thanks for any answers you can give.