I actually went with GM stuff for the most part. However, I have the odd duck of the group because I'm still using an MSD to control the spark which uses the stock Hemi cam and crank sensors. My Megasquirt gets a tach signal from the MSD box and just runs in batch fire mode, so I don't have sequential injection support, but also don't really care too much. I got the sensors with my computer setup, so I just swapped them in since it was a direct replacement for me and I didn't have to worry about recalibrating. Water temp senders are identical (aside from a different wiring connector I believe), and the air temp sender plugged right into a tapped hole that was already on my Indy intake. Throttle body is a Accel DFI unit that I think uses a Jeep style IAC and Ford TPS with a GM plug or something silly like that, so my setup is all over the board for components, but works just fine.
As said by others though, there's no reason you can't use the factory stuff minus a throttle body swap. My build is pretty one of a kind and pieced together because I originally performed a carb swap on the engine build and later came across a smoking deal on the computer so I just tried to use as much of what I already had as opposed to trying to keep things one brand. Replacing parts can be tricky from time to time since you have to know what came off what, but frankly my whole car was like that when I bought it. E body front brakes, C body radiator, now a B body axle, and all different years to boot, so going to the part store is always an adventure.
