If it's in the way, take it off. EGR, gone, MAP sensor bracket, c ya', intake, bye bye, upper motor mounts and clamshells, peace!
Get the car up even on 4 jackstands to give yourself room. Spray the stock bolts with PB blaster the night before.
Get a ratchet strap to hold the engine forward. A chain or something will work too bolted to where the clamshell for the upper motor mount was to get the rear header to drop in easier.
Get 2 new bolts for the crossover that are the same length as the included hardware and get 2 nuts and 3 washers for each. Use the bolt, 2 washers and one nut to make a stud out of the bolt. One on each end of the crossover on the side you think you'll have the hardest time getting to. I weld them into place personally but not everyone has access to ta welder. If you do, weld the bolt heads for the DP into the rear header too.
Don't tighten anything down until all pieces are in place and the hardware is is threaded somewhat. Tighten the headers then the crossover then the DP.
Take your time, use gloves, and get a blanket to set ontop of the engine because you will be kneeling up there.
Flip the swaybar upside down. Put an aftermarket one in while you're at it if you planned on doing that ever.