well, you should use D3 anytime you tow or have a large load in the vehicle. but i use d3 just like you stated - when i feel the need to zoom in traffic or need a burst in speed fast, i don't like to wait for the pcm to command it's time to downshift. manually do it! i'll keep in in d3 for the entire time of my manuvering or when i want to keep in in vtec range for an extended period of time(and for those of you who know the vtec range on a 00 AV6 you can guess what speeds i'm going)

wear and tear wise, the engine is running at a higher rpm, however, it's a honda. i wouldn't worry about it too much about it,especially if you change the oil on time. i use bg moa and feel confident in it's ability to make everything happy.

 

I had a 90Ex in the past and now have a 94 EX. Honda reduced the gear ratios beginning in 1994, probablyto increase gas mileage. I also noticed better acceleration in the 90EX. I see a significant reduction in RPM vs. MPH in 4th gear, 3000 at 70 vs. 2700 at 70 from memory. I also see better gas mileage, 32-33+ mpg at highway speed for the 94 Ex vs. 30 for the 90Ex. Note, the 90EX was not Vtec.

I looked at the gear ratio specs and indeed the differential gear ratio is significantly lower for the 94EX. Final 4th gear ratio is similar.

I hardly ever get to RPM's where Vtec is actuated, but my understanding is the transition is seamless and not-detectable as a "boost".

good luck

 

If you get a intake and exhust you might be able to feel it or hear it more. With my car i hear it and see it on the rpm tach. BUt its true it might be harder to detect with stock. BUt to be honest it is a sohc vtec,from what i read there is a gain in 20hpover the non-vtec motor. With Dohc you talking close to 50-60 hp. if you really want to feel the vtec drive a honda s2000.