Basically all latest generation projectors are quiet enough that you do not need to worry... around the 20 decibel mark. Thats probably quieter than your sky box.
Like a playstation, they also have fans which spin up faster if necessary.
During hot summer, if you watch a film then the fan might spin faster and be a little louder, but in general there is nothing at all to worry about here.
To my knowledge, there is no evidence to suggest that dlp offers better colour reproduction than LCD.
Normally, LCD vs DLP will produce a similar picture when in a similar price bracket. A chf 10k DLP will normally produce a better picture than a 4k LCD, and vice versa.
The main advantage of DLP projection was that, maybe more than five years ago, the pixel structure of some LCDs was apparent on the projected image (known as the chicken wire effect), whereas DLP did not project pixels and therefore did not exhibit such an effect.
This effect has basically been eradicated on last and latest generation LCDs, unless you want to sit closer than a meter to the wall (and if you do, factor in the cost of a psychiatrist into your budget).
The downside of DLP was that a small percentage, like less than 5%, tended to get a kind of motion sickness from the picture from DLPs, which is produced by a spinning colour wheel, a little like a kaleidoscope. DLPs color wheels these days are more complicated and spin faster, therefore the effect has also been largely reduced. Nevertheless, the stigma of this potential symptom remains a part of some peoples purchasing decision.
As a side note regarding the fact that you mentioned panasonic projectors (of which I have owned two and have been very happy with), and sanyo (my current projector being a sanyo), I can certainly recommend these brands of projectors. The similar Sony projectors have also been praised recently for their quality.
As for DLP, the major brands to look at include Optoma, Hitachi, Epson, BenQ, Infocus. I am less well informed about the DLP side of things however. Maybe NickH has more information on that side.