I had an 01 with yorshimera rs-3's. Now I'm looking to purchase an 04 that has erion pipes. Which are the better pipes and what would work better on the 04?

Sorry, no experience with either.
Supposedly the king of slip-ons are the Sato's low (standard) mounts.

My bike had a full system on it when I bought it used, so I replaced it with a full race Akrapovic. As such, I have never used slip-ons.

Others may be able to answer your question.

Bear in mind that for street use, mid-range rules.
Better to have great mid-range than top end.

I don't really know either but I do know that the Erion's are pretty damn good. Honda is what they cater to. Yosh is just a good all around can. I think you'll be fine with the Erion's. Like sub said the Sato's are the best as far as slipons go.

Thanks all. I gues I'll keep on the erions and if i don't like em , I'll get the satos!

Got to throw in my two cents. Like Sub, I'm running a full two into two Ti Akrapovic on my '03 with great results. While my comments are biased, I will say the previous owner ran a two into one Akrapovic system after scrapping the OE unit. He ended up buying the 2X2 which it now sports. His claim was that the 2X1 produced a slight gain in the mids, but those gains came with a significant loss of power in the higher RPM's. Just food for thought...