I had the Simota since April 2008. Early this year it pulled the wires out of the MAF connector harness. Maybe the removal of the balance shaft made the vibrations worse, and my car gets 35,000 or so miles put on it in a year. Perhaps most people won't ever run into a problem. The balance shaft removal didn't really make much of a difference in vibrations that I noticed, though. But I feel like I should at least let people know what happened in my case. My car has about 185,000 miles on it now, just to give you an idea how much it's driven (it's over 5.5 years old). Maybe the CorkSport rear motor mount insert would have made it worse? I wouldn't think so. If anything, I would think it would have made it less likely to have happened.
Personally, I recommend sticking with companies who have a ton of experience in Mazdas and have a known, long standing good reputation. CorkSport is one of those companies, and it's clear from the quality of this new intake. I used to think that SRIs were a pretty safe bet, but after my experience with the Simota, I'll be more careful with this particular performance upgrade in future cars.