Blower vs. NA: as long as the primary is big enough (sized for the boosted power, not the engine size or NA power) the length and equal or not matters much less, and saves $$, the chamber is always swept clean by fresh charge (not true with most turbos, which are extremely sensitive to high backpressure vs. boost pressure ratio).

Buying a Procharger: unless you get it from Scott or another trusted source, assume the brackets are too thin, and do what's needed. Many pictures, diagrams of blower brackets would cause a mechanical engineer to cry: metal and holes in the wrong places. Not an expert, but give me a good .jpg of the bracket and how it attaches, and I'll tell you if I see something wrong. Remember, "too thin" isn't the only error but it's common, and sometimes fixable with a simple 1/4" thick doubler plate (even a length of angle) bolted through the bracket assisting the stressed areas. Trust me, many people (who would never offer themselves as engineers) can intuitively "know" where the bracket will bend!