The difference is there and worth the 3 bills it costs. The bike will run smoother, cooler, and you'll gain a little HP on the top end. The more mods you make, the bigger the difference. I slapped on a set of bolt on Yoshi's on the busa, bike popped a little, ran just a little rough.. added PCIII and it smoothened out and elimiated most of the pops. Bolted on a complete Akra Evo 2 on the ZX10 and I won't say it ran like crap without the PCIII but the stock computer couldn't deliver the fuel the bike wanted above 9k and ran just a little rough everyware. With the PCIII added, OMG what a difference. The bike runs smooth, super strong and I think the PCIII removed 5 lbs from my front tire.
99 ZRX1100 - tons of mods and still slow but FUN /
07 Yami FZ1 for the wifie.