what dosent go wrong with the suspension

you'll have to forgive the tone of this post, but i'm slightly flustrated at the moment (read livid!!) right, i bought a 2001 V70 Bi-fuel in may with around 50,000 on it. since then we have piled on around 15,000 to take it up to 65,000 or there abouts. its just had a couple of front bushes, and a track rod end replaced about a month ago , and its still dragging me across the road in search of anything it can tramline on. my local volvo specalist is telling me that it could be ball joints or top suspension mounts (i think) but is there any part of the V70's front end that lasts more than 50,000 or is the whole lot a bad design??? could anyone give me some advice on what to look for, or list what the common problems are. the tyres are goodyear eagle F1's which went on about 6 months ago due to a puncture, so at least its not the pirelli's causing the problems. thanks

someone must be able to tell me what to look for. all i want is a car that drives in a straight line that doesn't make me or the wife travel sick.

All I can think of from the top of my head is have you had a full 4-wheel alignment done since these changes?