NotchBack Cherry Red headache .........

i recently purchased a red 1990 notchback ....it has and off road X pipe with mac exhaust ... i also noticed it has flex fan and under drive pullies........wow...lmao.. pretty much just what i wanted to get me back and forth to work after i crashed my daily driven race car *street car*...(i have a new apreciation for sleep now ) but anyway... the check engine light is on ...i noticed when i started the car for the first time for the day .. it would run very rough untill it warmed up.... so i thought it was the o2 sensors...but i also have an exhaust leak on the passenger side,the previous owner said it needs two bolts on the headers collector.....he also gave me some hooker shorty headers to thow on...so i figured ide do the headers and o2 sensors at the same time. ive been riding around and today i revved it up and popped the clutch spun the tires in a rolling burn out...took off and let the motor slow down the car while it was in gear........after that the car ran like a dog.....the exhaust leak sounded a lil louder.......i opened up the hood and the drivers side factory header was glowing bright red...im not sure what it could be ? i have no power at all now ....now when i start the car it revs and stays at 3K i slip the clutch a little and it comes back down to normal but still runs like a dog ..This car you can almost consider it a CHERRY .....it still has the factory airbox, just has bs exhaust ,flex fan and pullies ...i used the search button and the only thing i could come up with is retarted timing .....any other idea's guys????? im going to see if i can get my hands on a scanner tomorrow