oh, and i found i have a wicked exhaust leak today, i didn't know it was that bad. i can hold my hand over it and shut it off completely when idling....

 

definately fix the exhaust leak...

surging generally happens when the compressor wheel is turning too fast for the engine to injest the air it's trying to feed it, and the compressor stalls, and then speeds up really quick and that's when the boost needle bounces... and it ain't good for the turbo.

a smaller turbine housing will turn the compressor even faster...

but I would fix the exhaust leak first and see what happens

Forrest