do u mean ur gunna replace the 120.3 and 120.2 with a 120.4??? if so then id say the preformance will be decreased............

as for a push pull setup...thats exactly what im doing in my V2000b, im sitting two PA 120.3's in the bottom and using 1 rad to feed the GPU and the other the CPU.....id seriously suggest putting in two loops, 1 with CPU 1 for the GPU, the temps will b better overall and better preformance from the CPU