I have noticed since I built this car that there is oil present in the air filter and the air meter box. Long term is this bad? I had to replace the air filter at one point because it was so full of oil(k&n). Is the oil coming from the valve cover vent? Is an oil catch can on that vent line the answer?
Setup is: Century/BAE Turbo kit curretly set to 9psi
3/16" I.D. oil feed line to the turbo.
5/8" I.D. return going to oil pan.

it is from the crank case vent. I'd plumb it to a catch can to keep the blow by out of the crank case.

Is an oil catch can on that vent line the answer?

Sounds like it to me. I've seen some firewall mounted ones for airplanes that are pretty neat. If its not FAA certified, the price is reasonable.

Sounds like it to me. I've seen some firewall mounted ones for airplanes that are pretty neat. If its not FAA certified, the price is reasonable.

Where might I find a oil catch can? Would it go inline on the line coming off the valve cover?

There are loads of them on eBay. Also you could try Jegs or SummitRacing.

I had the same problem on a mazda that I turbocharged. There were two things going on in my case. The vaccume that was caused in the non pressure side of the intake when the turbo spooled was sucking oil out of the crank vent and also minor oil bypass on the compressor turbine seal was getting sprayed back out the intake and dripping down to the filter when the engine was stopped.