Time has moved on, transmission has moved on. These boxes are over 70% OE fitment, manual gearbox production is on the decline.
My advice, go 8HP, how you choose to drive it is up to you and your ability.
Same as anything, the more variables the more difficult things appear to achieve harmony on your product.
Trust me, I work in an OEM, our user interfaces look nothing like Maxx ecu, or motec or any of the after market stuff.