That's a tough one..... but here's a little info that may help you in your decision.

If the situation were "identical weights" (which it's not), we'd expect to see 1-3 MPH top speed difference between the two engines. Since the 175 ProXS is lighter, I'm going to say 1-2 MPH top speed difference (approximately).

The 200 ProXS would have a definite advantage on "holeshot", simply due to it's increased displacement. There is definitely a difference here!

Dependability wise.... consider them EQUAL. outside the 2.5 liter DFI block... the 175 ProXS shares MANY common components (externally) with the 225/250 ProXS (such as injectors, direct injectors, "multi-strike" coils, spark plugs, many sensors, etc). Still a VERY dependable engine!

The 200 ProXS is very similar to it's predecessor (the 200 DFI), with minor improvements that include Carbon Fiber Reeds, an improved air attenuator, improved calibration (PCM), and ProXS decals. It also uses a "single strike" coil (different from the 175/225/250 models).

I might also be inclined to consider the 175 ProXS if I were you.... unless you think you're going to need the extra displacement for your holeshot. It may simple come down to "dollars and cents" in the end....