Fuel, fuel, fuel, and did I mention fuel?
Detonation on any set up boosted or spray is a VERY BAD thing, a timing retard unit, and/or a window switch (spray only) is a great piece of insurance!
Yes boost can be as dangerious/hazardious as spray.
I have trashed more motors on boost than spray, but I prefer boost over spray though.
I have a box (mabey I'll dig it up and photograph it) of one of my pistons, it would make 8 people a nice paper wieght, that doesn't include the blck or the head.
If you take your time, and install the set-up correctly using all correct parts (don't cut ANY corners) and read and understand how each system works and why it does what it does, and how it does it.
Then you will feel more confident about using them and tuning them.
Wet systems are the sure fire way to go, but you can safey use a dry system if you do it right and don't push the envelope.
First thing to remember is that if you do anything to an engine that doesn't run right, this will definatly make it worse, peroid!
Make sure that your car runs "Top Notch" before you do anything like boost or spray, if not, don't point the finger at anyone but yourself, the out come will not be pretty!!
I you don't feel as thuogh you should install it yourself, find a system call the company and have them recomend a local install shop, then interview them, and mabey a customer or two.
and let me stress about oil, oil is the life blood of turbos and many cenrifical S/C's be sure to maintain it, and with spray, it contaminates the oil, so the more you use it, by far the more you need to step your changing intervals.
S/C and turbos are varible in power through out the RPM range, where-as the spray is only activated during WOT.
James was talking about tuning, if a chip is involved it will be the lastthing to be done, it's the cherry on the icecream, if this is not the case revert to back where I said about making sure your car runs "Top Notch"!
Be sure to try and tune on the dyno, I know it's a lot of monies but it's well worth it over a "wing it" type generic program that they'll pull out of thier file logs.
IE: I spent $130 some odd dollars for 12 viscious pulls with one of my 4 poppers and between the adj. cam sprocket and adjusting the boost I made 306 RWHP from 230 something, that 70 something horse power for $130, and all I did was read the hp/tq valuse @ per rpm w/the A/F reading per rpms and made my mechanical adjs., now that's what I call tuning and bang for the buck, how long did that take, not more than 45min on the dyno.