I'd buy it just for the red rockers!
Power is cam and compression dependent. This comes first then the intake, carb, exhaust as these are supporting characters. Not that good intake and exhaust components don't make improvements on other-wise weak engine internals, as they do, but the really big gains come from inside unless you're pasting a blower and/or nitrous on the outside.
These are Chinese castings, they tend to have porosity problems and often prove not to carry sufficient strength under the spring pocket. A common problem with big port heads, you just can't stuff everything in a box of limited size. You gotta watch the push rod length many of these require adding a lot of length on the push rod, this makes it pretty flexible so you have to step up to better push rods in terms of material used and/or diameter and/or wall thickness.
Haven't used these myself just passing on what I gleen looking over other peoples fenders.
Keep in mind the piston is part of the combustion chamber. While top end and cam improvements make plenty of power on there own better piston shapes really enhance what these parts do. So if you need pistons, this is always a good time for flat tops or D dish crowns as these configurations greatly support the effects of squish and quench which is where these modern heads are getting their fabulous power numbers from on unleaded E10/15 fuels.