I wouldn't use a side intake fan because it will blow against the natural airflow through the Tri-X heatsink-in through the fans at the bottom then out towards the case side through the heatsink fins.
If you use a side exhaust fan it'll help to exhaust the hot air, but it'll also rob the cooling fans of cool air, so only employ this option if your case has very strong front intake fans, in this case either will do the job perfectly well.
If it's a help I'm running exactly the same card in a Corsair Spec 03 case-Dual AP120 front intake (It has a dust filter and AF fans choke on it), single 120mm rear and a 200mm top, the case has no side vent. Speeds are controlled via a Sythe Kaze Master II-1200RPM front lower, 1100 front upper 1000RPM rear, 1000RPM top.
So far, not seen the card exceed 80C, more typically runs 75C in heavy games like FC4 or Metro LL Redux.
As you can guess from the tightly controlled speeds, I like a quiet as well as cool system. 😉