There's going to be rubber lines from the comperssor, about 12" and there's rubber lines from the expansion valve, through the firewall, and about 12". The remainder will be aluminum which will be neatly tucked away, following the contours as outlined.

As for being for the birds, yes they are. They clutter up the engine bay or at least for my purposes they clutter up the engine bay and get in the way for how my configuration of engine items is going to be. As for insulation, most MBs I see have the original insulation foam rotted away and the thick rubber hoses don't have any insulation other than their thickness.

My question should be re-phrased: Does converting from the original 2"+ thick rubber lines to aluminum lines negatively affect the operation of the AC?