you could put any brand on there ya want really, strange, afco, santhuff. QA1's are the only with the beehive shape spring so it'd sit in the factory pocket on the frame. TRZ has a locator that fits in that pocket and locates the 2.5" diameter coil.
You can use a t-bar at the bottom and bolt up like factory on the a-arm or swap to a coil-over specific a-arm like TRZ sells. But I'd bet you could buy the qa1 springs seperate and put them on any other brand shock and do away with the locator. The thing with the qa1 springs is there's I think only 2 rates to chose from and a coiul-over spring is endless in rates.
I deal with TRZ so if ya go that route and need a price shoot me a pm.