SR is more expensive than the Rb. And its not a “budget build” if you happen to get most parts for free. Its more like a “i got REALLY Good friends” build. Plus I had an extra crossmember, Rb20 harness, and spare rb20 parts from when I did my rb25 swap.
Take Brenden for example. His car was done and he probably did not spend much as he did most of the work himself. I still want him to do my intake manifold the way he did his.