Wiz, if you have the time. I'm assuming you guys made the calculation for spending the extra MP when teching and gain the ahead of time bonus, right? Now, I've only made a few calculations over it, but I think it will be only worth it to get the tech before than that when you are already at or very near the MP cap. Otherwise, if you really want to, 1 or 2 years before, but I don't think it would be worth it most of the time.
You don't actually have to eat any penalties to be ahead of time since it's based on whether the next tech would cost extra to buy. It's basically an incentive to stay current in tech rather than drop back a few techs to benefit from neighbour bonus.