Both are pretty neat setups. Meth Injection is more effective from a $/hp standpoint in the shortrun, but you do need to keep that tank filled. Tuning with an aftercooler is a good bit quicker than a methanol setup though and the overall setup is easy as pie. The only issue with the current crop of aftercoolers is that you CANNOT fit one on the EP3 JRSC manifold. You have to go to an RSX setup, which does require some homework. Not a huge deal, but something to think about. The best daily SC setup is a combo of both. I loved my SC'd K24/K20Z3. Just got too good of a deal on something else that I couldn't pass it up.

I wouldn't be too concerned about overspinning the Eaton Blower. There is quite a bit of margin on these things. It do however agree it is preferable to use add ons such as meth injection and the aftercooler vs. increasing compressor revs to achieve more than 10psi.