Just did mine at lunch time:
Time: took about 7 mins and I added 1 little (minor) touch to the mod
Results: you can definately tell the car is boosting faster now and it caught me off guard at first.
PROs: very easy, fast, and cheap mod (cost me less than $10) Noticeable mod ... I felt more change with this then I did with my $300 CAI.
CONs: for some reason my low traction light comes on when I take off ...

... this happens in 1st, 2nd, and 3rd gear.

If you enjoy watching the boost bar slowly climb, then you do not want this mod ... your boost shoots up very fast now.
There are already a couple of great threads on this topic and I had no new tips on the mod (other than black paint for "stealth mode") so here are my final install pics for my EDAL mod.
