Welcome to the club, I'm going to tell every new SRT-4 owner that buys a used car this -
CHECK FOR LEAKS!
Before you consider any power producing modifications, check all your vacuum lines for leaks and install some T-bolt clamps easily found on Napa, if you need a link to my detailed How-To let me know, its still on the SRT Forums.
Its cheap insurance against any headaches and post about I made this change and my car isn't as fast as I thought it was.
You can do a boost leak test as well, you can build one yourself or find somebody on the SRT Forums that sells them.
I personally didn't feel the need for a catch can, I replaced my PVC valve twice as the Owner's Manual suggested at mileage points. When I put T-bolt clamps on my car there was some oil on the exit side of the intercooler -
This was shortly after I got it and started making changes. I don't think crank case pressure is a problem with the stock turbo, I don't care what psi you run it at, after a certain point is produces more hot air than power anyway, certainly not enough pressure to cause problems. A check-valve would have been a better solution I guess, but as I said, once I changed my PVC, I never had a problem and I had disconnected the pipes a few times sense then.
Otherwise have fun...