I know where there is a brand new GTX3067 lying round, I was going to buy it when I was thinking of BT'ing my ED30.
You would need a rear housing but I was going to get a CTS manifold and rear housing, you can use your existing downpipe then.
On a CTS manifold and GTX3067 you would run 440bhp and a give torque curve with the right bits and mapping.