You already know my numbers. Everyones will be different as you've seen. If it was my car/decision I'd go with the manifolds and E/C retune. E/C has done enough of them to get close enough to be safe without a wide band. Both the downpipes and manifolds are proven. The wavetrac was big for me. It took me from 13 to 12 as I never learned to hook up with street tires and open diff. My car will spin the rear tires with the wavetrac going wide open throttle in 2nd. so you can understand why it's recommended. Choose the mod you can afford as the one's being considered by you are all worth while.

Les