Note that the output quality depends mostly on how good the laserdisc pressing is in the first place; some films had excellent transfers, others were very poor.
You do get a better picture with the higher spec players; it's not vast but the reduction in video noise level and jitter is noticeable.
The video on a laserdisc is stored as an analogue composite waveform. Using the SCART connection will not give you any improvement with a laserdisc player because it's still the same composite video signal that's output through the cable.
You might get an improvement using SCART if you have a player that's been modded to output RGB, or use the s-video output, but even then any improvement is dependent on the comb filter in the player being better than the comb filter in your display or capture device.
My D925 is loud when starting up or changing sides, but not particularly loud during normal playback. It's louder than a DVD player, but that's to be expected due to the sheer size of the disc! I don't know whether the noise of your player is inherent in the cheaper models, or whether it might be due to a a motor fault or misalignment.