After I installed my STI shortened lever I had occasional light rattling but hardly ever. Then I installed the TRD bracket and it is still rare. Only ever happens in midrange RPM and more than 50% throttle if I'm lucky. But I heard this happens even with everything stock (
http://www.ft86club.com/forums/showthread.php?t=98475). And I can instantly silence it when I lightly touch my palm to the shift knob.
Basically, the TRD shifter hasn't made anything worse.