I went with Overkill, and it's great.. I have absolutely no complaints with the tune, and it really woke my car up. The only problem with him is that it's literally like trying to squeeze blood out of a rock trying to get an email response from him on anything. I think my longest wait for a reply was a month. It can be super frustrating to be trying to find something out from him, and you check your email every day, but nothing nothing nothing. In the end though, the tune was good and I was happy with the product. He's just a really busy guy doing this as a hobby.
Then again, I've emailed Intense twice with questions about their products and never once got a reply... and that was over half a year ago.
I'd just go with the Overkill.