I have a 04 gt with sct,bbk plenum,bbk off road x pipe,flowmasters,thinking about shorty or equal length headers just wondering if they are worth the trouble
They are not. Longtubes are the only ones worth doing, and you'd have to get a new mid-pipe.
If you do not have gears, you should DEFINITELY get them first. 4.10s for NA, 3.73 if you plan on boost in the near future. You already have the tuner to adjust for them too.
I have 4.10s. It's not my daily driver but would recommend the 3.73s. I plan on switching back from 4.10 to 3.73. You go through the gears way to fast and highway driving with 4.10s are not good. Even in 5th gear your rpms are 2500 at 65. Not good on the motor. If you planning to race alot at the track and want the quickest quarter mile time then 4.10s.
I have long tube headers and they are a real pain to install. Plan on having a shop install them and ththe cost for install will be around 500 for labor. You will need it on a lift and the headers may need bent just a bit to get the fitment. Ive had my motor out 3 times. Headers were the best thing I did but the worst thing I could have installed.