I've been reading all sorts of complaints from people who have iPhone 4's and 5's in their RRS's.
I have a 2008 RRS Sc and the iPhone 4-s which appears to do everything I want apart from it doesn't transfer 100% of the contacts to the dash display.

Last week I was given a new iPhone 5 by my boss since he tried it and hated it!

What problems can I expect...for a start it doesn't link to my car with the Blue Tooth so I'm wary to continue messing about if all might be in vein. Ra-Ro Sport Super Dooper Charged.
Ford F350 Super Duty Prototype.
Ni$$@n Patrol 4.8 Overlander.

if you have the latest version of BT software (likely if you are already getting phonebook contacts list on the dash) then that year of module will only store 300 names.

iPhone 5 should connect OK to the car though. So there must be a setting on the phone stopipng it from doing so, or yoiu have your old phone and youve already got that connected to the car when trying to pair the iphone 5.

You can replace the module with a Discovery 4 module, but you need a connector with pins to give it power from the existing socket. That will give you 1000 contacts and much better quality.

UK Price is about £200 for the module.

There are some quirks with the way Iphone handles contacts, do a search for iphone 5 there is a recent post about this.  Bodsys Brake Bible
Software Updates Contact me
RRS Timed Heat/Remote kits - Contact me
BAS Engine Re-maps/ EGR Blank EuIII and EuIV
Clock On The Dash/ SNOTM /3Flash / BT Update /Service Reset/Error Codes read\ Gearbox Reset
See it HERE