Simplest (possibly the only?) way for Highline is to change the whole clocks, get them coded by someone who knows what they are doing. Mileage and functionality can be problematic on earlier cars I think.
There's a set of R32 clocks with Highline in the for sale section at £185.00 at the mo.
The MFSW buttons, simple to fit IF you have DSG wheel/DSG car, usually just plug and play (although I had to code mine), if your car is a manual it is a lot harder, needs additional controllers.
The RNS 510 shouldn't pose too many problems if yours is an Eddy, earlier cars can suffer from battery drain issues to due to some CAN gateway issue. I'm no expert so best pm'ing someone like Eddie-NL who will be able to assist no doubt.