I had the power blocks NA, then with the JRSC and then removed them. Also have the OFH, Perrin OP and 2.5" resonated cat-back.

NA, they moved the torque peak and fattened the mid-range torque a bit just as others have observed. At the track, my lap times were slightly faster (too slight to be significant data).

The dyno difference between JRSC with and without the power blocks was also insignificant (didn't even bother to change the tune after removing them after seeing the dyno runs)

The reason I removed the blocks is because it appears the rubber o-rings provided by Crawford can't handle some octane boosters, like Torco Accelerator. As you can see in the attached pic, one of the rings disintegrated on both straight edges. This resulted in a leak two hours into a road trip from Seattle to Sonoma and Laguna Seca (very painful failure) :(

I've been using Torco for years without any issue, mainly because modern intake systems (post ethanol additive gas) can handle it. But, it looks like the rubber in the o-rings can't (Torco is known for eating rubber). I didn't realize our cars had port injectors in addition to the direct injectors.

So, don't use octane boosters that eat rubber with the power blocks. Frankly, I don't think they are worth the bother in any case...

Does anyone know if Boostane contains Aniline or any chemical that will eat these rubber gaskets. I only have access to 92octane in WA, and live an hour from E85. I was thinking of putting a little Boostane in to get a 94octane mix so I don't pull timing and keep dropping IAM. but i have the CBPB and don't want to have any issues.