A decent stage 1 is a monumentally different car to the std car, esp in the torque department, can give better mpg as well, I would use a GGR stage 1 if I were you, I used a westfield version myself, it was stunning, or there is always Karl's gunship chip, a mix of stage 1 and 3 that works extremely well, Karl from NMS, Norris Motor Sport.
As said defo want to think about a better breather, these can be made diy for around £10.
tabetha