Different pipes and resulting powerband?

[m in sc]

you can get  aset of specII classics and run/extend the stinger tube down into the back cone a bit, but the sound change will be minimal. the triple guys have played with this a LOT. OR, Just fit some longer mufflers. all of this will affect the tune though.

[jmendoza]

To answer the original poster's question, here is my experience:

The 1983-4 Canuck RZ pipes are great for what you want as they are lighter than stock USA caty-verter pipes, the produce more power over the entire rev range, and, they are quiet.  The other big bonus is they fit the bike properly and have the correct dimples and bumpers for the center stand and side stand.
In 1985, the Canuck RZ350 pipes featured new stainless steel silencers and look very sporty, plus they deliver a little more power than the 1984 Canuck pipes.

Of all the aftermarket tuned pipes, the original Spec II pipes ( standard and pro) were about the best.  They have decent power from about 5K up to 10.5K, definitely more power than stock, and hit hard enough to require new clutch plates and/or 3 stiffer springs to keep the clutch from slipping.  The Toomeys have too little loo late as far a practical street riding goes as all the extra power is past 8500 RPM, making them not very usable in day to day driving and traffic. DGs feel great but basically have less power than stock. Same goes for Lomas/Scorpion.

One problem we have run into is many of the aftermarket pipes do not fit USA RZ350s properly.
There are issues with them hitting the center stand pivot bolt/bracket, hitting the lower lip of the chin cowl, center stand and side stand hit the pipes. The Spec II pipes have always fit properly.