Hi Vassilis, with "drop out" they mean a sudden drop in volume or a break (but we are talking about 1 second), but honestly I've never noticed it in Telegraph road.
With regard to the different masterings, I don't own an audiophile equipment and I can't notice substantial differences between West Germany and Japan releases. From a brief analysis of the preferences gathered around, there seems to be a larger appreciation for the West Germany versions, but not everyone agrees.
With regard to the different lenght of some songs, mostly it's a matter of seconds divided between music fading and a longer pause between songs. The only consistent (if one can use this term) difference is appreciable in SOS, where the final solo is a few seconds longer in the Warner Bros Japan and. IIRC, in the later "Made in USA" releases
As for the quality of mastering, I have read on audophiles forum that Dire Straits did not escape the very stupid "loudness war" of the 90s, and that the remasters suffer from (not as much as others, but still) compression (not in lossy vs. losseless terms of course, but in terms of dynamics being compressed, "brickwalled", so that the records sounds loud even in the quiet passages). Making Movies remaster is the most heavily criticised.
After years of reading on sound quality, I came to the following conclusions:
1/Plain,old, 16/44 standard redbook CD is more than adequate to store sound with utmost quality. Ultrasound can't be heard by definition, period, and 16 bit depth is more than enough for every level of sound the human ear can deal with. "High-resolution" 24/192 music, be it Neil Young's pono,SACD, DVD-A, or more recently "pure audio Blu Ray" are nothing but COMPLETE BULLSHIT. Differences in sound lies in the mastering, not the format. Even 320kb/s MP3 are just as good as CD when done right.
2/Nonetheless, a CD must be done right to sound great, and that's not often the case. Early CDs in the 80s suffered from bad A/D convertion process and bad D/A playbak systems. People put the blame of the format for music sounding "cold" and invented things like HDCD, with was bullshit as it required a propriatory decoding to sound "better". Unfortunatly some MK CDs, including GH and STP, were recorded with HDCD, and almost no HDCD player can be found now. Modern recording processes, such as the ones used in British Grove Studio, are way better than HDCD and do not require any special decoding.
3/So, the latter the better for CDs ? Not quite, because of the above mentionned "loudness wars". Even MK Cds are impacted...
So, it's complicated. Look for great mastering first, the format is not important !