I like the corvette guys answer waste his time to come into a different forum and post like what he is really saying is important probably he feels big and bad that he has a covertte and being 40yrs old nice, Im half his age and have an E55 06, um sucks to be you buddie and thats not my daily either.Most Si are 125mph stock. So I sure its around 125mph. The gearing of your transmission wont let it go past that also maybe 10mph or more.