Contemplating changing 01' to return style - Stock computer?
 

I am contemplating converting my 01' to a return style fuel system. As long as I keep the fuel pressure where the stock ecu is expecting it to be, any reason why the stock computer will freak out when it comes time for emissions testing?

I have thought about this.
Assuming you use a standard, referenced 43.5 FPR:
I think that if you simply remove the hose from the FPR (and cap the intake manifold port) then the FPR would revert to 43.5+14.7=58.2psia at the rail, fixed. This is pretty close to the 60psia at the tank. I think the stock ECU should be able to work with that.