[nonovurbizniz]

well i think it's a little irresponsible to say that if your compression is ok you can go turbo ( while true for the most part there's more to it than that.)

as far as no Intercooler it's possible at 5-7 psi but not advisable at all.

also the only way to truely be sure your not going to blow your motor is:

a: get the engine rebuilt/built for turbo
b: you need stand alone engine managment (your stock ecu will not be able to read the boost pressure coming in and it will not know to 1. retard the timing as the boost pressures increases 2. deliver MORE fuel as more boost is introduced 3. retard the timing if knock is sensed.

as far as longevity is concerned the more you invest initially will result in fewer maintanance problems in the future

ex.
if you dont get engine managment expect to blow your motor (unless your running 2-4psi but whats the point)

if you dont use an intercooler expect to blow your motor (sooner) (the hotter air will pre-dispose your car to detonation)

if you dont install a turbo timer (lets the car run for a given period of time in order to allow the turbo to cool down slowly) expect to blow your motor or your turbo much faster than a identical setup with a turbo timer (these things get REALLY hot and turning of the enging stops coolant and oil flow to the turbo. this is a tremendous shock to the turbo and all of it's parts. allowing it to cool down slowly will get MUCH more life out of the turbo)

and to answer your question the only additional noise you'll really notice with a turbo are:

spool up (depends on the turbo *just think about the whine you here next to a big truck on the highway thats the turbo spooling up (spooling up refers to the turbine spinning faster)

Blow Off Valve noise (when you shift gears the B.O.V. purges all pressure from the piping system (piping from the turbo to the intake) it makes a pssssst noise (you can route the bov to a filter so it doesn't make any noise)

the general exhaust tone will increase a little bit (mostly at high rpm when the turbo is at full boost.) but it's not that much louder (some exhaust's make your car way louder)

As far as installation if you can find a place that will do it they will charge you A lot of $$$. i cant imagine you finding someone to do it (at a real shop) for less than 500 bucks probobly WAY higher though