I'm planning on buying an SRT-4 within the next few months, but I am a little concerned by the fact that the turbo has an integrated wastegate. I know Mopar sells a BOV adapter, but I can't tell if it's to add on an aftermarket BOV or simply to make the noise. Anyone looked into it?

You seem slightly mixed up, a wastegate and BOV are two different things.
The wastegate is the method of controlling the boost produced by the turbocharger, it does this by bypassing the turbine when the set boost is reached. The vast majority of, if not all, factory wastegates are integrated into the turbine housing. Don't worry about an integrated wastegate, most stock turbochargers have them, and they work perfectly well. External wastegates are generally used on high performance applications, but rarely from the factory due to the added cost; they are better, but this is not to say the integrated wastegate does a poor job.
The BOV or compressor bypass valve is a device used after the fact, these protect the compressor side of the turbocharger by venting pressure built up against the throttle plate when you lift off the gas. Any BOV sold by Mopar will be fully functional, not just poser equipment to imitate the sound. Cheap insurance in my opinion, a good BOV will help your turbocharger live a long and useful life.

Oops...my mistake. However, now that I know that it does indeed have a BOV(the part I'm curious about), I would really like to know what the mopar BOV conversion kit really does. Direct from the Mopar Street catalog:

"The Mopar Blow Off Valve conversion kit maximizes the function of your vehicle's turbo system by venting excess, hot compressed air into the atmosphere, thereby reducing your intake air temperature. This kit adds a vent to the stock blow off valve and creates a unique turbo sound for your SRT-4 or PT Turbo."
So, what is the point of this kit? I thought a BOV's main function was to vent excess air, as stated by sluttypatton. It sounds to me like it's only there for auditory purposes.
I am still wondering if an aftermarket BOV would be feasible as well, such as the HKS Super Sequential or a greddy type S.

I have to admit, it does sound like Mopar is just blowing hot air. If the SRT-4 has a stock BOV that is fully functioning and prevents compressor surge, don't bother with the Mopar kit.

the stock bov vents back into the system and makes no noise, the mopar one vents to the atmosphere and makes the psshht sound, does not make more power just noise, has also been known to leak and lose boost

Cam lift is right all the mopar BOV is a piece of metal about 3/4 inch thich with Hole in center. which allows you to vent into atmospere making pssh sound instaed of back into system. No real power gains.

the stock bov vents back into the system and makes no noise, the mopar one vents to the atmosphere and makes the psshht sound, does not make more power just noise, has also been known to leak and lose boost

The only reason the mopar bov would leak or lose boost is if you have switched you vacuum lines around. It has been proven that it will not leak any boost.