Well, no slow down on system so the more the better I am thinking
More software = increased attack vector, more updates to manage, more potential internal conflicts especially if unknown overlaps are occurring on the system, etc.
More security software does not equal more protection, it is a case by case basis and depends on those security software, how those security software is used and how they work themselves, your system environment, your habits, etc.
KTS is a full suite, so I recommend you stick to either of what Umbra recommended as well. As for Sandboxie, if you're mainly using it for the browser sandboxing, I advise you use Kaspersky's safe browser instead... Kaspersky have virtualization.