For an E gas 986 (ie electronic rather than cable operated throttle body) you need a 74 mm Tb from a 3.6 Cayenne / 3.4 cayman or boxster or late model 2.7 cayman/boxster 996 605 115 01 / 997 605 115 00 and either the 996 tee 996 110 116 01 or the cayman tee 987 110 116 01 plus shorter screws 900 385 025 04 (4 off) , and larger clamps 90-110mm 999 512 539 01. You then need to buy two silicone reducers 102mm to 89mm (ideally 99 to 89 but they don't exist) plus some fabric tape (to pack out the slack on the intake tee under the silicone hose) and lengths of silicone tube to connect the air box / maf to the throttle body intake. If you use the 987 cayman inlet it may be possible to simply use the accordian tube from the 997 or cayman 987 to join the throttle body to the airbox/ maf 987 110 222 00 or 996 part 997 110 223 00.
You can identify the parts/ options using the online parts catalogue here :
http://www.porsche.com/all/media/pdf/originalparts/en/E_987_KATALOG.pdf
Just use the M97.20/21/22 option under the 987 model or the m96.05 under the 996 for 74mm TB parts.
Though i've not tried it , the 944 airbox tube looks like it may also be worth a look as a connector between the Throttle body and airbox housing if using the 996 tee, it already has a nice radiused curve.