The denso remakes are not OEM quality as they have different part#'s. The denso auto parts are not like the OEM auto parts. I have found this to be true when ordering denso fuel pumps from auto parts stores and comparing to my oem denso units. Not the same at all.
Well, my factory OEM A/F sensor lasted 80,095 miles and died due to a P1135. My replacement Denso "remake" (I don't believe that is the correct word as Denso made them in the first place) has lasted over 85,000 miles and is still going strong. I would not hesitate to buy another one, given the ridiculous premium price charged by dealers compared to what I paid on Amazon for the Denso. It sure looked identical when I changed it. I also have 75k on the rear one, but the original lasted 90k, so the jury is still out on that one.
I will also confirm all the O2 senors and all the A/F sensors are the same, within each type, except for wire length and the screw-in rear O2 sensors on the '01 and '02s. Cali's have 2 sensors, not 4, an A/F in front and a normal o2 in the rear. Even if the 2000 is a Cali'and has an A/F in front, you can use the rear sensor in front or back on your '97. Even if the 'new' one is too short, if you are good with a soldering gun you can splice your new sensor to your old plug and have plenty of length. Just the same as buying the universal O2 sensor that Denso sells. Not ideal as splices do fail, and need to be done well to be electrically transparent, but if you are on a budget...
I don't buy the 'can't transplant' story either. Sounds like dealer parts counter FUD rather than the truth. The vibration from being attached to the motor by a rigid pipe in daily life has to exceed the trauma from the transplant. I don't see a lot of stress going from the flange to the element. The screw-ins may indeed be different. Again, if the budget is tight, go ahead. The 2000 will have its share of miles, but if you are lucky, maybe it was a replacement. I'd say the majority of these sensors have already been replaced once by now, as both of mine have.
Finally, if you have a choice, use a rear sensor as your transplant. The temps are cooler post-cat so the rears last longer.