The Air/Fuel ratio in lean-burn mode on a VX is 24:1. Stochiometric is 14.7:1.
The VX was rated at 48-49 city (I've seen both) and 55-56 highway (ditto).
I bought my '95 VX with 194,000 miles on it in February 2008. I paid $1,100 at the dealer. After taxes, fees, I still paid under $1,300. The car had a new timing belt and water pump, as well as all other engine belts. The front brakes were new. I had the dealer adjust the valve lash and align it. Over the past year, I've replaced a CV joint boot, exhaust (cat-back), tires (80,000-mile Michelin Destiny tires 175-70R-13... BUY THESE TIRES!!! $220, installed at Tire Barn), rear brakes, oxygen sensor (NAPA quoted me $79 for the one for all other Civics. I showed up to buy it and they told me it would be $469. I raised hell and they gave me the VX one for $80.), distributer cap, rotor button, plugs (Champion), and plug wires. My total cost is less than $2,800 for a rust-free '95 VX with a perfect interior.
I still need to replace the input shaft bearing and I'd like to get a new windshield, as the current one looks sandblasted.
The car averaged 52 mpg in before winter. My wife has a very short commute, so the city mileage does not do it justice. When I drive it, I usually get 55+ mpg, as long as the A/C is off and I'm not taking forever to warm it up. During one trip over the summer, I kept the speed at 55-60 mph and got 66.7 mpg for the 400+ mile trip.
I agree that most VXs are overpriced. Don't give up if you want one. You may get lucky like I did.
Still, the VX is quite overrated. Most people would save more money overall by getting a DX. You can get them for around 2 grand versus the VX's inflated price of 3500+; and you can get 35 mpg out of them quite easily. Also, there's no rare, super expensive O2 sensor and cat converter to worry about.
You can't go wrong with any Civic. My wife's 01 EX makes very good power and gets 33mpg street, 40 highway.
There is nothing special about the O2 sensor in the VX except for the fact that it's a WIDEBAND opposed to those crap narrow band O2 sensors you get in most cars today. Narrow band can only say if the mixture is lean or rich, a Wideband O2 sensor can say HOW rich or lean the mixture is which is why it costs so much more. If you're doing engine tuning, you'll want a wideband O2 sensor so you can get the most from your engine, otherwise if you're an everyday shmuck, then a narrow band O2 sensor is just fine I suppose.