As I see it....the only way your going to get the best out of the car with the hp you have is if you can trap at nearer 7k, as you say it still pulls well there. Best way of doing that is to use the 28" tyre with a 4.56 gear, but thats probably not going to happen, so the only other way it can be done is with say a 29" tyre and try and run it out in 3rd. A 26" tyre will still only see you trapping at around 5400, not enough, and I don't think lash changes etc, will do much to help hp but it'll be fun trying I guess......my2c's