I'm very grateful for this thread as I too want to put a passenger side grab handle on my 2011 iMax. Here are the prices in New Zealand dollars. 1$NZ = 0.62$US.
858104H000TX TRIM ASSY-FR PILLAR LH $69.12
844804H000KD GRIP-GET ON/OFF $38.88
844814H000KD CAP-GRIP GET ON OFF $4.32
844814H010KD CAP-GRIP GET ON OFF $4.32
I also asked the dealer about the jack storage compartment. On a RH drive (mine) the jack is on the drivers side. The same area on the left (Passenger) side is a large void with only a wiring loom. I assumed a LHD vehicle would have the jack on the left and therefore a LHD plastic cover with access door would open up a very useful space for jumper leads etc. However this is not the case - the dealer replied "On investigation with the door scuff trim, it appears that also the LH drive vehicle has the jack compartment on the same side as RH drive vehicles".
After first trying my local dealer in Christchurch I found the dealer in Invercargill, Southland, much more helpful. They also got the sale of several engine overhaul items. I'll post a summary of the work and prices when finished. A new short block, turbo, intercooler, water pump, clutch, timing chain kit and belt are on the way. The head is being reconditioned as complete long engines for the 2011 are no longer available - only 2012 onward (plastic intake). Injectors etc will be checked and replaced if required. I'm also going to fit a bypass oil filter.
Thanks again for your part numbers and this forum.