Installing Aptana 3 on a Machine that has Flex Builder 3

I want to install Aptana 3 on my machine. I've got Flex Builder 3 (I think that I've got the standalone version, but I'm not sure). Both of them are Eclipse based. I don't want to cause a problem with either installation. Which version of Aptana should I download-- the standalone or plugin version? How can I tell which version of Flex Builder 3, I've got? I'm on a Mac.

Personally, I have a standalone Aptana Studio 3 and a standalone Flash Builder 4 (I had standalone versions of Flex Builder 3 and Aptana 3 before). I find that I prefer multiple standalone versions of Eclipse products because I see a degradation of performance in Eclipse and Eclipse-based IDEs when I load too many plugins into one.

FWIW, I have the following on my main system (also a Mac):

• Eclipse Standalone 3.6 with Amazon Web Services, ColdFusion (CFEclipse) and Java-related plug-ins for Java/CFML project (Aptana is installed as a plugin here for the occasional HTML/CSS/JavaScript work with these projects).
• Aptana Studio 3 for Rails work.
• Titanium Studio 1 for mobile development
• Flash Builder 4 for when I have to do Flex crap.

I know it might seem odd to have 4 IDEs (at the moment, I use Aptana and Titanium almost exclusively as my current workload is Rails and mobile development) but I find that all four run GREAT as is and when I start conflating plugins and features, I see degraded performance.

I hope this helps a little!