Don't know exactly where you're staying, but if you head to Argyle Street and start heading east (towards the city) until you reach PC World, then turn right down the road just before it and then first left, it'll get you to the Exhibition Centre station, which has an overpass leading to the SECC. Will be tonnes of walkers around for you to follow - the SECC carpark is a nightmare for getting out of so people will tend to park in that general area and walk over. (That's what I'm doing)
Would definitely be something special to hear STTG tomorrow, but I'll be happy whatever they play!
The car park just takes ages to get out of. As said previously if you park at the bridge, Minerva St (of Argyle st heading to the west end) then you'll get free parking and an easier off from the SECC