Forget about flashing - it's illegal in my state (NJ) and many others. Probably to prevent notifying drivers of upcoming speed traps.
There have been some great threads about "the rules for waving"
Interestingly, I also get the "cool car" wave, thumbs up, or nod from owners of newer Mustang GTs and the like. Also from drivers of older muscle cars.
On a major highway a year or two ago, a new Mustang Shelby GT500 and I did a mutual "thumbs up" after passing each other a few times to check each other out. The year before that, a repro Cobra 427 S/C and I had a raucous "show me what you've got" run down a local franchise freeway. Not racing, but showing each other some performance & sound (fyi, my '87 3.2 has a Dansk 2-out & a Fabspeed premuffler).
Bottom line: I'm probably more likely to get a wave from certain non-Porsche-driving "car guys" than I am from a newer 911. And I wave to them, if I like their ride.
BTW... Oh yeah, guys driving ricers seem to have a competition / inferiority complex thing. My attitude: I'm driving a PORSCHE 911 - I've got nothing to prove
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Here's a old thread that has the "Rules".....
http://forums.pelicanparts.com/off-topic-discussions/231387-porsche-wave-ten-simple-rules.html
That old thread regarding "the wave" is great - so much so that I summarized it a few years back when I first saw it.
IMHO, the best one is from an SWB owner (John Kramer):
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As a representative of the '64-68 community I would like to add:
1) SWB's are so rare by the time you see one from the front and can make out the longer horn grills, it's either too late to wave, or the car has rusted away;
2) By the time you see one from the side, and notice the tiny gap between the torsion tube cover and the wheel arch, it's too late to wave, or rust has begun to form;
3) By the time you see one from the back, and see the angled "911" script in gold, or the split engine lid grille, it's too late to wave, and the car is gone in a haze of Weber smoke.
Therefore, if you find yourself in a situation where SWB's are likely to be encountered, which is likely to be (a) a concours or the parade; or (b) outside of a rust removal/restoration shop, please do the following.
a) Boxster and 996/7 owners, please put your beer in the cupholder and salute;
b) 930 owners, please stop pointing at the boost gauge and wave;
c) 2.7 owners, please stop pointing at the oil temperature gauge and wave;and
d) 356 owners, please take your finger off the page of the NLA reproduction parts catalog, and wave to those whose parts are TRULY NLA!
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And from "larry47us":
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1- 356's get a Wave and Salute
2- ’67-‘73 911's get Two Thumbs Up
3- '74-‘77 911's get a Wave of Respect or Sympathy (your choice)
4- '78-‘83 911’s get the secret SCWDP Handshake
5- ’84-‘98 911's get an Enthusiastic Wave
6- 914's get a Knowing Smile and a Nod
7- 924, 928, 944, 968 get Eye Contact and a Nod
8- Boxsters get a wave only if they wave first
9- '99-‘05 911's - see Boxster
10- Cayenne owners get a raised eyebrow
11- "Special" Porsches (anything not covered previously), use your best judgment
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