In this particular episode most notably some driving scenes and car chase scenes were without sound effects and the scene where Doug is pressing KITT's "eject right" button and his bag flies to the sky is also without those beep etc. sounds.
Other episodes have altered music, for example the Prince song is changed for some generic "muzak" in the episode "White Line Warriors" for the second season DVD set. It doesn't actually bother me so much as the song is just playing in the background but missing sound effects are really obvious at least to me.
Have bought three sets of 3rd season DVD's and all of them have the same flaws, only the cases are different so they really haven't bothered much with region2 releases. Have read they fixed the sfx for US releases but as usual, haven't bothered with Euro versions.