I am making over 700 whp with my 2.5" piping with zero issues.

Also, I dont think the bends will make any difference as long as they are smooth bends and with no kinks. The air has to go somewhere anyway and the path of least resistance in this situation really doesnt matter IMO. It would be a good idea to keep the lengths down for response though.

 

Of course you won't have issues, thats not what I'm saying, you can make the power easier on bigger piping above a certain level/psi.

No difference when you start to have a restriction with exhaust gases at a certain diameter piping, and you upgrade, same thing applies to i/c piping.

 

I had a 3' on a different car and wish I wouldn't picked 2.5. Unless you are going for the moon, I don't think it's worth it. I think things like intake manifolds and 3' IC piping are only good for 650whp and above. You just lose response for top end power. One thing is nuts though is that when you blow off the piping, it'll sound like a damn shotgun blast just went off under your hood!

 

If you use 3" keep the piping as smooth and short as possible. dont route it in some retarded manner.

 

Exhaust gases and cool air charge are 2 totally different animals. Exhaust gases, being extremely hot, need larger tubing to flow large amounts of air through because of the expanded molecules of air from the heat. Cool charge air reacts just the opposite. The cool charge air doesnt need as large of tubing to flow large amounts of air because the molecules are contracted. To a point you are correct in saying that you will eventually need to go larger with the charge piping, but from my experience in seeing dyno runs between 2.5" charge piping and 3" charge piping on a 800 whp EVO, the difference in size of charge piping didnt change a thing. I would assume that when you start to exceed around 800 whp, you may want to upgrade to 3" charge piping, but until then, you should be just fine.