Vacuum hose length needed?

[dwd1985]

Dont anyone dare tell me to do a search, because I have been looking through old threads for nearly 2 hours trying to find the answer to my question. I found part of my answer, but I need to know the rest. First of all, my idle is really low, and when I shift from park to drive, the RPM's dip almost down to nothing, and then go back up to around 500. The same thing happens when I brake, the RPM's dip, and then go back to 500. I'm thinking this could mean a loss of vacuum. Also, I have been getting a code 34, which is the EGR solenoid valve. I have heard it can throw this code when vacuum hoses are loose or leaking, so I am getting ready to remove the intake mainifold, and replace all of the vacuum hoses, and clean or replace the EGR valve. I have found through searching that instead of using stock subaru hoses, I can use 1/8'' viton hose, which has a higher heat rating. So if I need to order a length of this hose, how long does it need to be, and where can I order it from?

My second question is, I have found through searching that the idle from the factory is 600 RPM's, but what I havent found specified is, is that while the car is in park, or is that while it is in drive but stoppped with your foot on the brake?

P.S.: Also, as long as the intake is off, is there anything else that I will need/want to replace as long as I am under there?