I installed an Evolution Motorsports high-flow intake in my '03 Boxster.
Disclaimer: This is not a DIY guide - I'm writing this up to give you an idea of what you're in for if you elect to do this install yourself. As the directions state, this
is a difficult install - if you're not a DIYer (i.e. you don't do brakes or oil changes), this install is probably out of your league.
No instructions come in the box. You will want to have the EVOMS
install guide handy.
I removed my factory airbox in pieces (I'd seen someone else describe using that technique). This was not my initial intention - I was going to remove the driver-side intake manifold per the instructions. After removing the throttle body and half of the manfold bolts, I wussed out, put those parts back together, and used nippers to cut the OEM airbox in half to get it out.
Getting the old airbox out, whether you demolish it like I did or go the classy route and loosen the driver-side intake manifold, is the hard part of this install. Whichever route you go, this part's gonna suck. If you use the technique I did and break up and remove the factory airbox, BE CAREFUL! There are injector wires, sensor wires, and wires for stuff I couldn't begin to explain in the area of the airbox, so don't get sloppy!
Installing all of the Evolution parts takes all of 15-30 minutes. Piece of cake. The most difficult part of the install is threading and tightening the two bolts in the bottom edge of the new air enclosure. A combination of reaching down from the top and reaching up from below (a floor jack and a creeper really come in handy) will help a lot.
I rate this a 7 on my own DIY difficulty scale. For reference, I'd rate brakes a 2, rotors a 3, headers a 3.5 or a 4, and secondary cat bypass pipes a 6. It's definitely doable.
After I get some more driving time in, I'll post a response with sound and throttle impressions.
sd_boxster 
Threaded Mode
