I noticed after a long stretch, heavy on the pipe. When I let off it seems to backfire, a couple times. Is this ok?

 

Depends on what pipe you have. Is it totally stock?Baffle removed?
Some aftermarket pipes are too free flowing and tend to cause a backfire on letoff.
If its stock, then its running lean on the idle circuit. Either an intake leak, or exhaust leak, or the mixture screw needs to be richer.