I drive a diesel car and van and they are both quieter than that
Wheels look guffing
That's a pointless comparison. If you look, you'll see that the cylinders have covers over them to prevent anyone seeing what the finished item will look like. Who knows what that does to the acoustics?
In practice, you'd expect the new bike to be mechanically quieter than the old one since the cylinders, as well as the heads, are now encased in water jackets.
Besides which, your van probably has a plastic engine cover, under-bonnet sound proofing and its engine is encased in getting on for 2 tons of steel bodywork.
New GS 1300
1300GS
If the M1300GS is a performance road variant, I don't see how there is room left for the S1000XR. I suspect the M1300GS may be an offroad-biased Rallye HP replacement... would be brilliant if it came with a 15kg weight saving over the R1300GS.
Will the R1400GS be 100cc more (and probably +20kg over the R13GS) or will it be the same R13 motor with no change in output? (following BMW's car model nomenclature where number no longer equates to engine displacement)
So:
R1300GS = road-biased performance
M1300GS = offroad biased
R1400GS = fatboy ATGNI version
The 1300 gs will be a stunning engine.