The B04T has the same performance as the B03 basically the engines are the same, I cannot build more B03 engines because I have run out of cooling-heads, so we use the Light version of the B02T and I also am using the same crankshaft as the B02T inside this engine which has the IBOND hardcoating.
Milage is about the same as the B03 but this depends also a lot on your driving style and car efficiency.