I put the best headers I could find,didn't want fitment issue or corrsion problems,and wanted a good power and torque making design...went with the Kooks!
Did the install,in my shop,dropping the K-member is the way to go. Before you drop the K-member,scribe some location lines around the flange areas,to help with reinstallation. I went a step further and drill 2, 1/4 inch dia. locating holes,at the rear mounting flange. These were slip fit holes,and by using 2 pins,you line it up,slip the pins in, then tighten up the bolts,then remove pins. It is right back in it's place!
If you don't have a CAI kit,get a good one,like a JLT, to improve intake airflow,plus a good tune.
These steps really woke up my Bullitt!