To check for wastegate actuator rod length, go to volvospeed.com, or easternaerospace.com, for instructions on how to change the length. It's pretty easy. When you get there, look at the before and after pictures. Often, when the length is shortened too much, not enough exhaust gas is being allowed to escape, thus creating an overboost situation that the ecu figures is a problem, and in doing so, dials back boost.

When you hit your top speed, what rpms are you at? Do the rpm's keep increasing until the just smoothly stop? Or do they hit a certain rpm, and then drop down a little, and then increase again, but only to the same rpm? 130mph sounds like a good speed for the limiter to kick in, so I wouldn't be surprised, and I know for a fact, that the newer Volvo's have them. If you do have a limiter, there isn't anything you can do about it, short of having your ecu reprogrammed or chipped.