I don´t know about 2012 wk2, but there´s a member here that did something similar to what you want to do but in a wk (2005 or 2007, don´t remember), he´s "svenskajeepguy" (http://www.jeepgarage.org/members/svenskajeepguy-992.html
) very nice guy btw, you should ask him your concerns (here´s his post about his car transformation: SvenskaJeepGuy's 2006 Midnight Blue Build Thread
Also, check on ebay for seats (srt8 seats are awesome), srt door panels, srt Steering wheel (you lost this: http://www.ebay.com/itm/SRT-SRT8-Int...p2047675.l2557
ALSO, check on ebay for a store called "pick_a_part" I bought from them, very pro.
they sell used parts, and send worldwide (I bought them srt8 seats and they send them to me to Chile) their webpage is http://www.clevelandpickapart.com/
(maybe you can ask them if the cluster works in a limited)
For turbos, no idea, BUT check VORTECH for grand cherokee on ebay just in case.
Best of luck!!! Suerte!!