Poor running t-cat

[nightfirem10]

Hey guys, We installed a swamp xl on a 2009 T-Cat, it pulls really hard, but it runs poorly, backfires,hard starting, doesn't like to run when it is cold etc... Do you have any suggestions? On the listing you guys have listed that it requires no fuel mapping mods. Do you still hold that as true? Is there anything you can recommend, and does it have any timing changes?
All info would be appreciated at this time,
Alan

[Mike/HMF]

The unit we had in for R&D ran terrible when it was delivered to us. After nursing it around a while it eventually started running better. We came to the conclusion that the fuel was bad. It ran great with the exhaust and no other mods. We found that even with the exhaust installed, the engine still ran a bit rich in spots. If you had to do anything with fueling it would be to take it away in a few areas.