Dude, RAW is in no way clear here. Therefore, our interpretations are different. They way you are putting it is that your interpretation is correct, and all others are incorrect. I'm not saying you're wrong, I'm saying I disagree with your reading of the rules. It really doesn't matter either, because you will probably never my GM, just like I will probably never be yours.
Also, Charybdis and I aren't exactly the unenlightened minority here. If you look at the link I provided, you'll see that we're not the only ones who believe that this wording is ambiguous, and that there are a lot of good reasons for disagreeing with your reading. Again, RAW is confusing here considering obviously different opinions of what "internal" means. To me, it would seem that an internal system is inseparable from the weapon unless you put in some serious work (i.e. a weapon modification). I cannot conceive of an internal AND easily removable system that doesn't require some kind of weapon modification. You clearly disagree, which is fine. Again, I'm not saying you're wrong, I'm just saying I disagree.