FYI, Integral Audio took apart my car to do acoustic measurements, just as they did on the E90.
They said it came apart and went together with quality, in their opinion just as good as the E90. They did not find any decrease in build quality at all.
'98 Dinan/RMS stage 2+(VAC cams, CES Cutring etc)
'15 Buick Regal "T"(wife)
'06 Saab 9-5 Combi 5mt (full suspension, LSD, clipped turbo etc)