no problem...
accessing the engine is easy. you want to press the conv top button to raise the 'clamshell' (the part that covers the conv top when it's down) to its highest position in its arc of motion and let go of the conv top button. get out of the car and go to the clamshell you just raised. you need to unclip the rear of the conv top from here. if you look down into the area that the clamshell covers, you will see that the very back of the conv top fabric has a piece of fabric with a long bar that runs the length of the wall that separates this area from the rear trunk. the bar clips under 2 clips (1 on each side) that hold it in place. just unclip it from these two clips. next, on each side of the car, there are black cables that hold the back of the conv top tight to the car. they have silver ends on them that attach to ball sockets. you can just pop them off with your hand or a screwdriver. now you are going to swing the back edge of the conv top 'up' towards the front of the car. if you're on the driver's side of the car, imagine that the back of the conv top is at 3 o'clock. you're going to move it so that the back edge is at 12 o'clock. (you'll want to do this on a warm day or you'll risk cracking the plastic rear window like i did.) this whole procedure is also covered in your owner's manual.
after that, you'll need to remove the rear shelf (the storage compartment behind the seats) out from the back (mine has fasteners that you just need to turn 90 degrees to remove). then remove the carpet piece on top of the engine. now you're at the engine cover. turn the fasteners 180 degrees (or until they unfasten! :D ) and pull the metal cover off (be careful you don't scratch your car!)
ta da, you're at the engine. you can change the air filter if you want, but i'd wait for your oil change (or not - it's up to you.) other than that, there's nothing else to do here. oil and plugs and everything else are done from under the car. sorry...
as for your ignition switch, it sounds kinda strange that they didn't have the part, and then they had the part. did all this happen over 15 minutes, or did they have enough time to actually GET an ignition switch from a dealer, etc? unfortunately, there's really no way to tell if the ignition switch is new - unless you know the part number of the original switch and the part was updated with a new part number which is printed on the switch itself. it would be a lot of work to check this. i'd take their word for it. ;)
you haven't answered my question about the clutch pedal. you're sure it's all the way down and you hear a click when you press it, yes? sometimes i don't press mine all the way down and i'm like WTF, but then i press a little harder and vroom-vroom. that's why i'm asking. with you being new to the car, i can see how this could happen.
here are some pics of the Air/Oil Separator (A/OS or AOS). the picture labeled DSC4797.jpg is a very good pic taken from the passenger's side. on the left side of the photo, the (top of the) AOS is that round piece of plastic before the plastic piece with 3 'fingers' that says 'porsche' on it. notice also that there is a 'J-tube' that comes out of the AOS and connects to the throttle body. if you replace your AOS, you'll need this tube also.
http://renee.devetter.home.comcast.net/boxster/oilsep/
here are some other great boxster links that can help you with just about anything:
http://mike.focke.googlepages.com/mikespor...boxsterwebpages
http://www.986faq.com/
http://boxster.wikia.com/wiki/Main_Page
also, check out http://www.ppbb.com if you haven't already. lots of helpful people there too.
and don't forget, the 'search forum' button is your friend. there's TONS of info here. B)