If you go to 9:1 your boost potential will be limited a bit. What model are you working with? Without an intercooler you will be limited to around 8 to 10 pounds boost. I've seen the results of too much boost on a 1.9 first hand. Blown Arias 8:1 through both top ring lands is not pretty. Also if this is GT the spacing to put one in is kinda tight.