My comments build off of yours...

What I see is the same when comparing QFT Q-Series with comparable size Proform "Race" carbs:
- Main body and boosters; they even have both companies' names on the main body castings, regardless of carb brand
- Metering blocks (4-emulsion holes) with pre-drilled threaded e-holes, except where blocked off by undrilled e-jets
- Jets, IFRs, MABs, IABs, emulsion configuration
- Float bowls (I'm A$$uming the same floats, N&S & hardware, too)

What I see that is different when comparing QFT Q-Series with comparable size Proform "Race" carbs:
- Baseplate throttle shafts
--> Q-Series throttle shafts are "slabbed" (thinned), whereas Proform are unmachined (round)
--> Q-Series throttle shafts are installed using teflon bushings, IIRC, whereas Proform shafts ride against the anodized aluminum surface
--> Color (BFD)... Q-Series have red anodized metering blocks, base plates, etc., whereas Proforms are anodized purple
--> There are more carb sizes & booster options available from QFT than Proform; Proform does offer a couple of those only as separate main bodies (e.g., 1.59" venturi w/ annular boosters)

I only compared QFT's Q-Series with Proform "Race" carbs, because QFT's Race-Q lineup uses some different components than the Q-Series, such as:
- Metering blocks with 5 emulsion holes, e-jets in all emulsion holes, and a different emulsion configuration
- Base plates with "dual pattern" 4150/4500 mounting holes
- Bearings used w/ the shafts installation as an upgrade to the simple Teflon bushings, IIRC

I have noticed that although the Q-Series and Race-Q share the same main bodies & boosters for the same size, their tunes aren't always the same. That's probably because they have different emulsion characteristics due to different metering blocks, which can certainly impact the tune.