I have replaced the outer boot on both my drive shafts. In fact, you can buy a boot kit from Volvo for about $70 US. It consists of two boots (inner and outer), two band clamps, and the grease. I'm guessing that only the outer boot is torn, in which case, you can do what I did and go to an import auto parts store and just buy the outer boot, band clamp, and grease for less than $10. Make sure you get the right boot, as I think the turbo shafts are thicker. The whole job takes me about 4 hours start to finish, but I'm not a pro and I'm very finicky. I think I've seen one of the pros that frequents this site state it takes him about 3 hours. I can't imagine the "part" costing $799 - that's about three times what the entire driveshaft (CV joints, axel, boots, etc.) should cost. My advice is to get an honest, reputable person to do your work. In any case, get it done ASAP. A tempory alternative if you're short on cash is to get one of the universal split boots and put that on yourself. It's just a matter of cutting the old one off and slipping the split boot over the CV joint, making sure to put in the grease. That should last you until you get it done properly.