I know a lot of people are using AMS but I was wondering what is your thoughts on the ETS one.

This is the one i'm planning to go with, would I need anything else to change out the ralliart with this one?
http://www.extremeturbosystems.com/E...ooler-Kit.html

They also have a ralliart one
http://www.extremeturbosystems.com/E...-Pipe-Kit.html

 

I've got the ETS Ralliart specific one, including the upper pipe and the materials and finish are great. They make sure you get all the right couplers as well when you tell them what you plan to do, ie keep the stock LICP, etc.

Unless you plan on building a monster, the 3" core is more than enough to cool the hair dryer of a turbo in the RA.