They're about increasing reliability and longevity.
Pyro gauge (exhaust temp) lets you know when you need to back off the skinny pedal towing.
PCV re-route stops the PCV gasses from being circulated into your intake and clogging stuff up.
Block plate stops exhaust gasses from being circulated back into your intake.
Larger down pipe to replace the squished factory one will drop your EGTs
Exhaust will drop your EGTs.
Lift pump adds another water seperator and another fuel filter along with taking some strain off the CP3
EFI live is your tow tune. Not really a must but I really like my tow tune with turbo brake.
2006 2500HD CCSB, 4x4
EFI Live by Idaho Rob, Banks CAI, AirDog 165 4G, PPE fuel ports, Sinister EGR Cooler, PCV Reroute, Diamond Eye downpipe, Turbo Back 4", Kryptonite upper a-arms, MOOG SD lower ball joints, Sleeved MOOG SD tie rods, MOOG problem solver Pitman and Idler w/PISK,
Kryptonite Transmission Support, Firestone Ride Rite, Bilstein 5100s, B&W Turnover, Curt Class V