My JBA shorty's were a real PITA to install on the drivers side!
The passenger side, not so much. Only really had to lift up and relocate the coolant bypass hoses out of the way of the shorty's to ensure no rubbing and melting...lol
As for sealing up; took the advice of a gifted MOPAR tech I know that specializes in heavy performance upgrades for all makes and models of MOPAR's...
"get top quality orange RTV and lay thick, heavy beads of it on the collectors where the cats bolt up to the shorty headers so it oozes out".
He said if this is done right and let to set and harden with a hoist warm in process... there shouldn't be leaks.
I've put almost 8,000km's on my new headers, and quiet as a church mouse, in terms of no exhaust leaks.
Now, at WOT with my current set up, including a FastMan TB and good RL 5W30 oil.... she howl's like a happy & healthy HEMI should "Our Lady of Blessed Acceleration, Don't Fail Us Now"!