I would not expect anything in the way of a four pin flat harness, nor aftermarket to have proper integration with the BMW wiring functionality. As I wanted to be able to tow at full weight, whilst gaining the benefit of the vehicle dynamics controller WITH the trailer attached, I did the BMW wiring kit.
To the best of my knowledge, Stealth and Invisihitch both use OEM wiring. If you look at the installation manual for the Stealth, it parallels that of the OEM.
It's worth figuring out if you already have the towing module installed (mine did) even without the wiring.
Unfortunately not. However the OEM wiring is supplied with a Pollak 4/7 pin combo. I started with this:
https://www.etrailer.com/Accessories...k/HM40978.html and then made an aluminum bracket that clamps to the rear pinch seam to mount it to. My desire was to not have to drill any painted parts on the rear my X5.
You DO want to do some coding after installation, as there are options for the OEM wiring other than just PDC zoom (z.B. I enabled the trailer DRLs when I coded mine).
I'd have to pull bits and pieces of my conversations with Almaretto, but if you have Esys, then yes, you'll able to get it sorted. In short:
For the hitch wiring:
1) FA Code 3AC
2) Code the AAG Module to most current CAFD to match the vehicle I-Step level
3) Edit the CAFD to change the entries back to default for the hitch type. This ends up being:
3100 Hitch_Common_1, FA
3101 Hitch_Common_2, 32
4) Code the FDL back into the AAG->CAFD file
IIRC, doing the FA coding automatically enabled the trailer zoom option.
Feel free to PM for more info.
I have the Curt on mine and have been quite pleased. The safety chain loops are a little on the small side. I've been using their towing products for years, and still feel they're a step above the DrawTite/HiddenHitch/Reese Towing conglomerate. At the end of the day, I wanted a US style 2" receiver that I could put any standard ball mount into and have a number of different height configurations to match my trailers.
All of the "hidden" hitches only offer one fixed height solution per ball size. Moreover their 2" receivers are not intended for full load towing.
For a ball-mount I'm using a Fastway Aluminum with a Stainless Curt Ball. I HATE the Northeast oxidation.
FWIW, I'm also fairly close to having the ability to make a trailer controller harness that will plug directly into the OEM integration.
My Solution:
Home made 18' car trailer...
Installation Instructions
Curt 13077 Hitch
1x 82 71 2 349 500 - Electronics Installation Kit, Towing
1x 71 60 6 884 357 - Control Unit (Already installed in my CPO X5 35d)
8x 07 11 9 906 050 - Hex Nut
8x 07 14 7 293 278 - Rivet, Black
HM40978 Bracket
Custom aluminum clamp ~3 bucks of 1.5" Aluminum Square bar and a night shooting the shit at a friends basement machine shop.