Hi guys. I have a 1998 Ek2 EL (yes it's an EL not EX) hatchback with a D13b engine. It came stock with fuel injection. I just got a 3 stage VTEC head and I want to do a minime build. The 3 stage VTEC head is obd2 with a P2J ECU. The D13b is odb1. I am going for fuel economy and not power. My question is, which is better...

1. The d13b bottom with the 3 stage VTEC head. (P2J is non tuneable).

2. The d13b bottom with same d13b head and a chipped P28 (tuned for fuel economy)

3. The d13b bottom with a 2 stage VTEC head and a chipped P28 (tuned for fuel economy)

With a long gear manual transmission.

Which of these setup will give me the best fuel economy?