Has anyone purchased the new Bachmann Spectrum F7 A/B unit? Just curious about the construction and quality. It "looks" nice in the LHS display case...but how does it run? The other Spectrum diesels I have run pretty loudly (compared to the Kato and IMT engines) so I'm wondering if this one is the same. Secondly, has anyone changed the couplers on Spectrum engines over to the Microtrain coupler? Easy process? Any problems?