Do I need an ECU tune after bolt-on upgrades?

[YellowBoxster951]

2000 boxster S, manual trans with 70k.

I am doing the following over the next few weeks and already have all the parts needed:

987 airbox with hi flo intake (pedro)
997 tb and plenum
de-snorkel
fabspeed exhaust w/ sport cats
short throw (this one doesn't really matter for this question)
and POSSIBLY underdrive pulley but I'm on the fence about it.

After these upgrades will the ecu learn how to run the car or do I need a tune?

Also, while I am in there tooling around, do you have any other performance
upgrade recommendations for me? I dont race it, just weekend canyon carving.

Thanks!