TRC off... maybe u pressed a button or something something that switched your traction control off. If so, just press it again when ur done drifting like one guy said...
If VSC always on... dunno, maybe u screwed the Vehicle Stability Control and it needs checking...
It's not about Airtrek but more in general. My Airtrek comes with clear windows (local USF car), but I've tinted the rear doors, rear side panel and rear windscreen 75% tint. Using it for 4 years now, no problems...