Regarding the blower, I suggest budgeting for £10,000 (that is GBP) rather than $8,000 (kit, shipping, customs, etc). Richard already implied something along those lines in an earlier post. And that will be for Stage 1. So, add another 50% for Stage 2 and an additional 50% for Stage 3. And that will not be the end of it. I am pretty sure that a larger/thicker-core radiator and/or oil cooler will be on the menu as well, plus plumbing, plus, plus. I do not imagine that I will be happy to shell out that much to whip 4ss and then be forced to have 'sympathy with the engine' when it starts running too hot.
I am not sold on the Carpenter-style drive-in-drive-out solutions either. Been there, done that. No way am I going to put my brand new Rocket motor up for a heart-and-lung transplant. I will rather wait till motors start appearing on eBay and elsewhere, buy one and offer that for major surgery. And I will have my original motor as a ready replacement when I detonate the souped-up one. So, probably $4,000 + $8,000 + start jotting down the list.
Also, keep in mind that the new Rocket engine has gone on a serious diet compared to the previous generation. Everything that could have been made lighter has been made lighter - therefore also weaker and less forgiving. That includes the drive-shaft. More power, less weight and affordable - choose any two.
Patience. At the rate these new Rockets are selling, we will soon see throttle-body/air-cleaner solutions, more radical cams and more exhaust options come to market. Any good combination of that, complete with some already proven Penner-magic, should satisfy most - even the more demanding. Unless, of course, you need to have it all.