OK, so I have been reading this and I have a question. I want to go from my 3.08 to a 3.55 on my THM. Will this work or do I need to go smaller? The build sheet says the "performance" gear for the 400 with THM is 3.23. Is this is big as I should/can go? The 3.55 was available, but maybe for the manual transmissions, both 3 & 4 speeds I believe. Anyhow, I am looking to get a better 'launch" out of my car but I do not want it to run at too high RPM on the highway. I do VERY LIMITED highway driving. Will the 3.55 work? Will it be a big difference on the launch?