Intercooler for 1999 Mustang GT

So I have been doing some research and I found a cheap intercooler setup that I could do as it is a DIY Kit for my 1999 mustang gt that has a vortech supercharger on it.

Here is a link to the kit

http://cgi.ebay.com/ebaymotors/ws/e...50333494747&ssPageName=ADME:X:AAQ:MOTORS:1123

Anyways I asked the guys selling the product this question:

"Hello I have a 1999 Mustang GT with a vortech v-1 s trim supercharger running 10 psi and what is my loss in psi? Does that mean I should change my pulley to keep my 10 psi?"

Just-intercoolers response:
"sorry,I'm not sure."

So I then now turn to all of you for some insight and logic on what should I do? I began to think, with an intercooler I should gain about respectively 30-60rwhp right? However I do lose 1-2 psi due to all the piping. So if I lose the psi but gain the rwhp from the intercooler I don't really need to change my pulley to accomodate for the lost boost? I will dyno before and after I get the intercooler on to make sure I haven't lost that much hp. I am at around 425rwhp so I dont wanna blow my engine up. I have a 3.3inch pully on the supercharger. Anyone know what I should do?