I looked at both, and decided on the V6, although the V8 is a fine choice. I chose the V6 model for the following reasons:
- Acceleration is basically identical since the V6 has shorter gearing, so it gets off the line quickly. As well, it feels more taught when you step on the gas at speed, a positive driving characteristic.
- Less weight over the front wheels - since the V6 weighs a good bit less than the V8, there's less front weight bias and thus less understeer. The car respondes better with the V6 to transitional changes as well.
Some things didn't matter to me - Price wise, a V8 is about identical to a V6 with the PP package, and it gets about the same mpg, but it takes more oil on changes and more
spark plugs, so maint is a little higher. Still, its a miniscule difference, but with a V6 and shorter gearing, I don't see the need for the V8.
The Aisin transmission is a great transmission - Aisin is the ZF of Asia and is in some of the best driving cars ever, including the Honda S2000 and Mazda Miata, as well as all Toyotas and Lexuses, so you know its reliable.
At the end of the day, I could get everything I wanted on either car with either engine, so I would have gotten either. I went with the V6 as I fond it a better handler, and think 290 hp is plenty with the shorter gearing, and got the exact color I wanted. If you have a deal on a V8 lined up, you're not losing out by going with one over another imo.