now it won't start!!!!!!!

Had plugs, wires and fuel filter installed car seemed to be running rich, some nice backfires with the new downpipe.

soooooo

any ideas?

most of the obvious stuff I have tried.

 

obvious like rechecking the plugs? you may have flooded it, and now the plugs are fouled...yes already. do a search on flood, flooded, flooding, etc. Lots of posts about what to do. I let my car sit and the battery was low. I kept trying to get it to turn over, flooded it, had to buy new plugs. It happens.