List your best mods (or most wished for) in each of these three categories:

Efficiency (mpg or km/liter)
Performance
Cosmetic

Mine:

Efficiency: Intake. I saw almost 2mpg improvement on my old modified stock airbox with the drop in K&N.

Performance: Probably a tie between the Jet Stage 2 chip and the 2.2" pulley on the SC.

Cosmetic: The new intake/cai setup. Enough said.

Efficiency: Intake. Similar results

Performance: 2.25" SC pulley or 72mm TB and miniAFC

Cosmetic: '02 chrome 17" wheels

Efficiency: Dunno

Performance: True Ram Air

Cosmetic: True, good looking, Ram Air hood (And new paint)

You have a ram air hood?

Sorry, mine fall under "Most wished for.." part of the topic...

efficiency-cold air intake

performance-2.2 pulley

cosmetic-7 color underbody kit

Effiency: What'* that? My right foot prevents it.
Performance: Gotta be the intake. Love the noise it makes.
Cosmetic: Ooooh. Tie between the HID'* and the drop springs.

Effieciency : haha
Performance : Intake baby
Cosmetic : 18" Chrome ..looks fantabulous when the car is movin

Efficiency: 48MPH of pure TC Lockup
Performance: hahaha, nothing
Cosmetic: The beautiful look of stock with chipping paint.

What i got
Efficiency: O2 sensor / STP
Performance: Ram Air
Cosmetic: Tail Tint/ Gold class wax
Sound: Deck and subs

What i want
Efficiency: Custom Intake
Performance: Jet Stage 2
Cosmetic: 17" Enkie 5+
Sound: Dual exhaust tips... behind a flowmaster