IneednSC

Well i have the a340e trans in my car with my 1j which is being replaced soon so i want to try and do something with the trans while its out, i want to stay auto because i just like to cruise but i want my trans to be able to hold 450-500 hp and not die on me after a year. I dont know much about these trans so whats the best route to take for about $1300? Is it even worth spending money on it?