They are the same compressor wheel sizes. Industrials HP turbo however is 2mm smaller. The only difference between RCDs work stocks and towpowers is the amount of blades on the LP and you have the option of a billet wheel on the HP. Towpowers also have some exhaust side work, I beleive they have a larger exhaust turbine, how much I'm unsure. As for power differences I'm sure they wouldn't be any more than 10hp. The only way you could gauge is identical trucks with different turbos either drag strip or same dyno.