I recently faced a similar choice. '02 Lexus RX300 for $20k or '02 X5 for $30k. I bought the X5...

I just did this install last weekend and my notes are posted at the bottom of the DIY. There's no way you're gonna' get the quality of the BMW kit for $200. The lighting harness kit alone is gonna' cost you another $160 and it's plug 'n play, not splice 'n pray. Comes complete with 4-wire electronic converter and round to flat connector converter.

I was tempted to cheap-out on the hitch too. Went OEM and darn glad that I did.

Patrick