I need some personal advise on this matter. I have a local dealership who is currently selling me the New Silverado HD2500 with LMM motor for 2K below invoice and in-stock for delivery today. I also have a GMC dealership who willing to sell a 2007 GMC Classic HD2500 LBZ for 2K below invoice as well. I understand the LMM is a new design with all that new smog crap but should I be concerned about reliability????? :help