Retrofit Bluetooth kit for Yeti integration with Bolero

cheers,

i want to buy a bluetooth extension for the original Bolero installed in my

so i can dial from the touch screen, get dial ID at the Maxidot etc.

i though about

http://www.ebay.com/itm/VW-Bluetooth-KIT-unit-3C8035730B-5N0035730D-VW-Skoda-Seat-/330630866865?pt=Car_Audio_Video&hash=item4cfb22a7b1&vxp=mtr#ht_500wt_1287

and on Car Systems here http://www.carsystems.pl/vw-bluetooth-kit-5n0035730d-retrofit,id221.html for the same price.

i have few questions:

1. do i have cheaper alternatives ?

2. do they ship it with installation instructions or i can download it from anywhere ?

3. i understand need special codes to connect it to my bolero ? where can i get these codes from ?

thanks.

p.s. i swear to God, i googled it many times before posting this question and couldnt find the answers for that :-)

thanks again.

avner.