I did the PPE Air Box Mod on my '07 LBZ last night... pretty simple mod. No real noticeable difference in turbo noise or power, but I've been taking it as easy as possible... going for fuel economy here.

My question is, someone mentioned that they thought I should need a boost gauge and a new air filter when doing this mod. I haven't seen this in any of my research, thoughts?

You will not need a boost gauge unless you are running a good size tune, which it doesn't look like you are.

As far as the air filter, if it needs replacing-replace it. If it doesn't, don't worry about it.

I would install a pyrometer/EGT gauge before a boost gauge...mainly to make sure EGTs are at least below 400 degrees before shutting off the engine, and monitoring while towing.