-- Lens shift question => The lens shifts are specified as plus/minus 80%, vertical, & 34%, horizontal. These are from the screen center. Therefore you are dealing with half screen dimensions (as others have stated somewhat differently). For my 106" screen, it's 92" wide and 52" high. That means that I could place the HD250 anywhere between 0.8 x 52 = 41.6" above screen center to 41.6" below screen center (provided I used zero horizontal shift). The horizontal lens shift works the same way, but you use the screen width instead.
Since the amount of horizontal lens shift used subtracts from the amount of vertical lens shift available, the use of any significant horizontal lens shift is discouraged. As Daniel (I believe) stated, your HD250 (or any other PJ
) should be mounted so that the center of the lens is at about the horizontal center of your screen. That way, only very small amount of horizontal lens shift will be needed to "tweak" the horizontal alignment. this leaves the majority of vertical lens shift available for use (that's what is really needed for most installations, anyway).CFR
-- My Mitsubishi HC5500 is rated "below 19dB" in the low lamp mode with it's measly 160W lamp (about 22dB in the high lamp mode, which I don't use). The HD250 (from the JVC site) states that the HD250 is rated at 19dB with it's 200W lamp. My PJ is on a shelf behind my left shoulder. The exhaust vent is about 18" from my left ear, and I don't hear it, since it is right at my room's noise floor. Accordingly, I don't think the JVC PJs (even the 220W RS40 & up) would be much more audible. Anything in the 19 to 21dB rating should be great (especially if your PJ is further from your head than mine is). Normal room noise floor is typically rated at 20dB (for a quiet room).
I lived with my old DLP PJ and it's 26dB fan noise, even though it was mounted in the same location. But that one was definitely noticeable (by me) if the audio was on the quiet side (especially if the movie story line didn't "pull me in" -- just about any action-adventure flick, especially science-fiction).
If your, proposed, HD250 were further away from your ears (than mine), it should also be totally unnoticeable. That's one of the advantages of a larger, physical, PJ -- they are usually quieter. They are certainly a whole lot quieter than any of the Epson PJs.
Yes I have the HC5500 and I'm still enjoying it (2670 hours on the 5000 hour rated lamp - low lamp mode). That's why I'm holding off on any upgrades for 2011 (even though it's very difficult to suppress the urge). That way, as I said in the "Over $3K" forum JVC thread, that I will (can likely) afford to get the 2012 model replacement for the RS40 (or possibly even the RS50 --