I understand what you mean. Here is something to ponder.

If you go with the 400, are you sure you won't regret going with the 460?

For me, I always want to upgrade. I have seen too many people settle for something smaller and then wish they would have gone bigger. It could be the size of a motor, lift kit, or even a garage you build. It seems common to regret staying with the smaller option. You always wish you had a couple more square footage in your garage and I think if you stick with the 400, you will wish you had some more cubic inches.

Hope this helps.