98 to 00 AWD used a viscous coupling to sense changes in traction at the individual corners and applied power accordingly. The biggest problem then became unequal tire circumferences making the computer believe that there were different traction issues going on and then misapplying power. Using the mini spare for more than 25 miles is a no-no. Having this car towed by anything other than a "roll-back" is a no-no. If you have to replace a tire, you replace the entire set. Keeping wear patterns equal and tire pressures equal is a main issue with these vehicles. To that end I bought a $100 air compressor from Home Depot and valve stems that show airpressure ($13) from my local auto parts guys to simplify this problem. If you have a need for AWD, don't be afraid, just know the issues and deal with them. If you don't need AWD, don't pay the extra $2500 or so for the vehicle. I am happy with my 2000 v70 xc. You might also consider the cost of an extended warranty for an AWD if you have concerns about this.