each part on their own are for show. altogether, boltons are necessary for future motor modification.

I/H/E is always the basic bolt on combo people go with. say if you were to change cams, the bolton combo would then become truly useful, but until then, the combo is pretty much useless, as the three together cost about $1000 for the top quality brand names, yet only yield ~10hp altogether. now with a set of stage 2 Crower cams and a valvetrain upgrade, you'll hit about 15hp... with the boltons, you could hit upwards of 20. with a computer upgrade to raise your rev limit, you are then able to really maximize the ability of the cams, giving you upwards of 25hp. with a good port and polish, you could conceivably hit 30hp with just cams and valvetrain.... but of course, it's half that without all the other addons.