I have both an '03 AP1 and an '06 AP2, love both. I wrote an article about my feelings a while back.
part 1 here and part 2 here

If I were buying one now, I would probably get an '06 or later as others have stated. But -- My daily is the '03 and I am sure many would disagree, but I feel it is a more pure sportscar experience. The '06 is faster, and the wider wheels really improve the handling on the Autocross track.

 

They changed it due to morons not knowing how to drive, don't over rev your motor and you'll be fine.
2000 changes and the AP2 still isn't any faster.

 

if you thought a heavier flywheel was the cure to blown motors you NEED to get your facts straight. Dont blame the car when it was all completely driver error. "nahh lates" lol and if you even knew who Dan was you'd also know that he is a very helpful and credible resource over the years, yourself?? not so much, you are the guy that was trying to fit +12 offset volks right?? . Also an ap2 at its stock limiter is not doing the same piston speeds an F20 does at its limiter.

 

You are correct in saying that they didn't revise the AP1 for no reason. They revised it so that people who do not know how to drive wouldn't be quite as likely to destroy the car.

???
I'm *hardly* saying I'm a great driver by suggesting that I'm in the top 5% of the motoring public. I'd be *very* surprised if I'm not in the top 0.5% of the motoring public. At the track, I'd *like* to think I'm better than average amongst those of us who semi-casually track our cars several times a year, but realistically I'm only average in that group. But this is a group of people who actually know (more or less) how to drive a car at its limits, as opposed to the "motoring public" who, by and large, do NOT. What percentage of the motoring public regularly tracks their cars? Not many, certainly less than 5%, probably less than 0.5%.

Anyway, the heavier flywheel was for people who don't know how to drive, not to make the AP2 "better" for those of us who know how to drive.

 

04-05 require a whole different ecu, so that wouldnt be possible, the heavier flywheel in AP2 has a purpose, lighter flywheel is way more prone to blowing your engine, building up higher revs gives you less time to fix it on a $$ shift... dont get caught up on all this 9k rpm... when the displacement was moved to a 2.2 the 8k rpm is equal to 9k on a 2.0
AP2 ftw 08-09
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The only thing to be gained by 9k rpm in an AP2 is the sound of 9k rpm, which is nice to have. You can rev an F22 to 8.5k easily, and I believe 9k, but Honda limits it. Honda also lowered the power band so power comes on sooner, so an S owner isn't exactly missing anything with the F22 other than the sound of 9k.

At any rate, the 04-05 fixed all that was wrong with the earlier years and improved much of what was left. Its still not perfect, but its the best you can get before you move to DBW. I'm not anti DBW, but I do like mechanical better, so, 04-05. If I had to get a DBW, 08-09.

 

Just to be clear, those 2,000 changes weren't made because people blew their engines, you have to remember, the S2000 was an engineer-driven car. The team kept tweaking the car throughout the years, making little improvements here and there, and the big set of improvements with the 04. Why exactly the flywheel got heavier isn't known but we can all speculate. One thing though - flywheel weight as a design consideration is often chosen for defining the character of the car, not just performance. I suspect Honda added the heavier flywheel for both safety and stability purposes.

The end result was a slightly faster car that feels more secure and stable. Some people don't like that compared to the AP1 - to each their own, but they made the car easier to drive.

 

They made it easier to drive.

 

I just picked up a 2001 with 36,000 miles on it but with 11,000 miles on an AP2 motor and transmission that was installed in it back in 2005 or 06.
They kept the original electronics so it still revs to 9k.
Sweet little car....

 

You might want to search around the forums on save rev limit for an F22 motor. 9000 long-term is not doable. 8600 is considered the absolute highest you should go and many people will say 8400-8500 for the extra safety/longevity.

 

Its not just absolute rpm either - look at the power curves - there's no point in revving much higher than 8,300 rpm, which is the stock cut off, and really nothing above 8,500 rpm or so. When Honda re-engineered the F series engine, it moved the power curve down around 1,000 rpm, so it didn't need the higher redline.

For reference, a Mazda RX-8 rotary engine could spin as high as 14k rpm or so, but it makes no power, so the rev limit is 9k.