X-Games Star Malcolm Stewart -- Check Out My $5 Million Car Collection!!

Move over Floyd ... X-Games star Malcolm Stewart is proving extreme athletes have swag too ... and the proof is his $5 MILLION CAR COLLECTION.

Stewart -- who took third in the Red Bull Straight Rhythm race at the '14 X-Games -- tells TMZ Sports he's been building his 14-car collection with his father for years now ... buying and working on the rides himself.

These whips ain't for cruisin' though ... Malcolm says he NEVER drives the cars (some of them have never even touch the road) and they are strictly to be shown at high end car classic car shows.

His most expensive ride? The1969 Copo Camaro which Stewart says is worth a minimum of $500k ... but could go for up to ONE MILLION to the right buyer.