I have Straight shots but a buddy from work has the long shots on his 1600 classic. No FMS such as PCIII or TFI. His plugs are good in color his bikes runs great and in the last 1 1/2 has put quite a few miles on it. I have also disconnect my PCIII and everything is fine. In my opinion I would install the pipes and drive it easy for a week or two and if you have no back firring then check the plugs every 2 or 3 days. If they are not running hot then I would say save the money for another mod or beer for the summer.
