Both instruction sets not too dissimliar to what VIDA has to say and both pretty ugly considering. I just took a look at the front bar on my XC and the brackets are indeed on top of the subframe but are located quite close to the wheel end of the bar. Just about where the boots on the steering rack are. You just might, and I say might, be able to get a closed-end wrench on both the bolts of each bracket and loosen them. Since I was just looking in thru the wheel opening, I can't tell, however, if there is enough clearance with the subframe bolted up to allow the rearward bracket bolt to be fully loosened and removed. Looks to be pretty tight there. Front bolt looks doable. On the assumption that both bolts are removable, then it should be no problem to replace just the bushing with the alternatives I've already mentioned. In any case, using IPD instructions to lower the rear of the subframe to the amount they specify then it would be fairly easy to replace just the bushing. No real need to replace the whole assembly per the "official" way.
I have to say this chassis is about the worse I've seen for this job. They've really tucked the bars up and out of the way which is bad enough, but then to do like they have in back with a non-standard approach to mounting; it really looks like they have gone out of their way to guarantee work to the dealers and the Volvo parts business.
Cheers,
Bill