Get a boost gauge and a pod and mount them on the A-Pillar. Get the Dawes Device, AKA G-valve, and have some fun. Make sure it's set to stock pressure at first, ie about 8 psi, and get used to the operation. Check all your hoses o make sure there are no splits or cracks and that all connections are tight. This is the cheapest and most cost effective boost controller ever. Don't go for the high boost right off or you can destroy the engine. If knock occurs, it will throw a rod for sure. There is an underdash cutout switch set at about 13 psi.

The pod etc can be purchased at IPD, or use e-gauges.com and get a pod seperatly. MVPVOLVO has them too.

I made a G-Valve but the heat hardened the epoxy and one of the plastic barbs broke off causing excessive boost. I backed off quickly. No damage occured.