If it's the guibo, you'll know it when you look at it. Guibos that have failed to the point of making vibrations like this are very visibly destroyed.
If it's not the guibo, it's failed universal joints. 170,000km is a bit early for them to fail (more like 170,000mi) - but if it's the case, you're looking at about $500 for a new driveshaft, as the joints aren't serviceable.
The failure symptoms of each are pretty similar; as they're both exacerbated by torque. Only slight difference is that a failed guibo will shake all the time (more when torqued), while a u-joint will only tend to shake when it's torqued the most (on a manual; upper end of 1st gear and lower end of 2nd).
My money's on the driveshaft. :\