E70 hitch/ harness install / programming question

[Kormaster]

So my 2012 X5 50i is a lease and i dont want to cut the bumper trim. So I decided to get aftermarket one that tucks under the trunk. I still need to trim on the bottom but at least it is not completely trimmed.

I decided on OEM Harness 71-60-2-156-526 - about $200.18 from tisher bmw.
and I just ordered Tekonsha 90250 Prodigy RF Electronic Brake Control



Now, about programming - is it completely necessary? Some dealers want $500 for programming, some want $280, some wont touch it since I will install the harness.

Ill be towing 5000# open trailer with a race car. trailer will have dual electric brakes on both axels. Some people tell me the car will be fine without all those fancy stability control programming. I personally dont need rear view camera option for towing or my PDC beeping wont bother me (ill just turn it off).

Without programming, will i get power to the harness for signal and brake lights? Brake controller I got seemed to work by plugging in trailer harness to brake controller, then from brake controoler, it plugs into T1 7 pinn connector of the car. No other wires needed. It is calibrated by RF signal from the front with a remote.

I live in socal.. any dealer experience with regards to programming? My distance of travel will be as much as 500 miles one day to race track but typically 300-400 mile round trip to Buttonwillow/Willowsprings.

Thanks guys