JB4 all the way! I had the JB3 which was awesome and now I have the JB4 which is incredible! The power is very smoothe and being able to switch maps on the fly is really nice to have. The sweetest part about the JB4 is the adjustable shift light and how u can turn ur gas gauge into a boost gauge! Plus if you've heard of the "golf tee mod", the JB4 controls that can flap which I love because the car sounds much berlier at idle. Also the "max cool mode" is a must for in between races to cool off ur engine if you don't have an oil cooler. Hope this helped. Love the JB4 if u can't tell
