Turbo trashed?

[spiffy926]

So I just installed the new turbo, and at first it seemed to run great. It started easier than ever, and didn't seem to be burning any oil.
But then after I let it warm up for 20 mins or so, I tried driving it a little.
After a couple full throttle runs, to test how the boost was building, it hung at 4k rpm, and kept on dieseling. I had to chunk it into 4th to kill the engine.
It never really ran away, but rather just hung in the higher rpms.
I would describe the smoke coming out of the tail pipe to be white, maybe a tad blue-ish but also keep in mind the exhaust system is thickly coated with oily sludge.

Now I am worried my compression might be suffering.
I find it unlikely that the IP is mis-adjusted because I never had any issues of this nature running the old turbo, or running N/A.

Is it possible an intake, or exhaust leak could cause run-on?
I had to re-use gaskets when I switched the manifold and turbo.

Also would it be worth the time to flush out the fuel system before I investigate compression issues? I should also note that you can visibly see smoke coming out of the breather, and the oil cap will hop a little bit.
I'm not sure to what degree these two things are normal.

Any advice will be appreciated, thanks.