Hi Aimtimes to answer your questions it all depends on you.
1. If the oem switch for heated seats is not in your X. You will have to buy it. Possibly ebay or parted out X like I did. Appears to be standard on 4.6's and 4.8's
2. scale of pulling out the carpet. 2. 2 being very easy.
3.Unbolting the seat is neccessary. They hid \ziptied the wire directly under the rear area of the front seat but they zip tied to the metal in the front. I pulled center console out because alot of threads on here said you had to. "After doing this I feel you still have to lift the center console up in the back because you still have to fish the rear heat seat wires back to where the switches mount." " sliding the seat wont get the job done" Nope look at the back on the ground of your front seat. You see the the airvent.. under it is a hump. That hump in the carpet under the airvent is where the wire is ziptied to the frame. Unbolting is neccesarry to gain clearance and to safely cut the ziptie.
4. HEHE both.. the heating elements I used are older from my kia sorento before I crashed it. It used the older 2 wire method. Most heat elements on the market nowadays are 3 wire design. mine werent. So Ihad to modify the circuit to allow 3 wire design ( thermistor). I wanted as oem look as possible. that meant wiring, connectors, switches.
Most aftermarket heat elements you buy come with there own non oem switch like a rocker. if you do buy aftermarket and want to use oem switchs make sure you buy dual stage heating elements. Mine were single stage thats why I had to modify the circuit. ( BMW uses 2 different temps hi,med and off for the heating elements) kia only used 1 hot and off.
If you want plug and play I think its $400 to $1,000 usd for used or new rear seat covers with the elements in it. Because BMW sews their elemements into the leather.
Any more questions feel free to ask.
my total= $100 for all the bmw connectors from stealership. Now we know part numbers about $24 - $50 bucks online.
oem switches - ebay possibly $25 to $50 bucks
mine were parted out - got 5 parts for 100 bucks
1 oem relay, 2 rear seat lights,2 rear switches, 1 cig lighter cover.
oem relay - $5 to $10 bucks online
hogring pliers and hog rings - $25 off ebay.
heat elements I already had but originally $100 ebay about $120 to $150
new diagonal pliers/cutters $20 bucks at home depot- mine sucked had toget new ones made a whole lot of difference.
2 thermistors to make dual stage elements - $6.64
1 trip to stealer to reset the airbag light..- forgot to fully disconnect the battery terminal..just did the big ground wire.. $75 effing bucks. DOH.
time and effort really 2 weekends 1 weekend to rip front seats out and center console out and search for wires but since I showed basic location could be done in 4 hours tops
1 weekend to pull out rear seats and install elements.. uhm first time.. now i know how to do it. possibly 1 whole day.
2 weeks of waiting on bmw connectors. 1 week of waiting in thermistors
1 week waiting for the parts to ship.
so its really up to you. But like i said i am now looking into ways of cooling seats rear and front. like ac vents and thermoelectric. I may even use thermo electric sample to have heated and cooled cup holders
Thermoelectric Device Demonstration Peltier Effect - Cooling - YouTube. heheh.