One thing to remember when it comes to folks selling stuff, they're gonna push either what they have on hand, or what they can get a better price on! As for wide angle support goes, how wide do you plan on going? The Master Technika can handle lenses as short as 75mm (fairly wide for a 4x5) without needing the accessory focusing device, and with cammed focusing.
You need to think about what you're going to be shooting, and how you're going to do it. If you want to be able to hand hold the camera at all, and not have to focus on the ground glass, then you'll need the rangefinder! If you never plan on shooting that way, then it's really not needed. Same goes with the wide angle focusing ability. If you're planning on shooting with a 53mm lens most of the time, then the MT isn't the camera for you. I think you'll find that either the MT or the 2000 are fairly heavy cameras, so a slight difference in weight shouldn't be a deciding factor, but rather weigh the 2 cameras capabilities for what YOU want to do with them.
As another option, there's currently an APUG member who has a Technika IV listed for sale on this website at what I think is an outragously low price, along with a couple of lenses. Here's the link to the listing:
(there was a url link here which no longer exists)
Of the lenses he has for sale, the 90mm SA might be from the camera, you'll want to ask if the serial number on it, and the 90mm cam match. Even if the cam doesn't match, and while Linhof will tell you that the cams MUST match the lens/camera (with the IV they must also match the camera, with the V and later only the lens) I've found that I've been able to use a couple of mismatched cams with fairly good luck. One is a 135mm cam that seems right on, and the other is a 210mm cam that's fairly close, certainly close enough when stopped down, it might not work for wide open shooting. Of course, considering that you are looking at NEW Linhofs, you could certainly buy a used one, then spend the extra $250/lens to get Linhof to match a cam for you! Personally I suspect the need to have the cam so perfectly matched is just an example of German precision, with the old Crown & Speed Graphics, you could get stock cams, and they worked fine. You might want to contact that member, see if they'll let you try before you buy, or something like that, or heck, at the prices they want, just buy it and try it, you can always sell it if you don't like it.
-Mike