I talked to a guy who said that upgrading stuff like intake, exhaust, headers, etc. is a waste of time because you will always ultimately be stunted by the catylitic converter, which i dont want to remove. He said thats the biggest thing and unless you replace the cam shaft or do a bunch of gnarly s***, dont waste the $$$. Can anyone validate or disprove that? Or has anyone noticed a difference in the V6 SR5 by doing those things?

I agree with this to some degree. Exhaust flow will only be as good as the most restrictive component in the exhaust. My very expensive TRD duals did nothing for performance because both catalysts remain.

how do they sound though?

Based on reading these fora for a year now, there are a lot of good things you can do for the non-VVTi motors. Lots of dynos, anecdotes and whatnot espousing the benefits of modified exhausts, headers, unichips, etc... I have yet to see any consistent feedback on effective mods for the VVTi motors. Seems Toyota done mod'd them up already.

I was going to get a new exhaust just to do something, but I heard a friend's Flowmaster and hated it. Maybe 20 years ago, but I think I might be a stock muffler kinda guy these days.

Tom

how do they sound though?
They sound fine. Nice controlled growl only a decibel or two louder than stock. There is a slight drone at lower rpms but not too much. Fit and finish is excellent though, but no performance increase. :cry:

I own a non-vvti tundra so I don't pay much attention to the vvti info because it doesn't suit me but I have read some information on this site about this same thing and the question that I have not yet seen answered is:

Has anyone with a vvti motor upgraded headers, intake (even just drop in filter) and exhaust all at the same time?

This would be the real difference in whether or not it is a waste of money to upgrade the vvti motor.

If you just put a new exhaust on and don't change the 4-on-a-log manifold to higher flowing headers and don't get more air into the engine all at the same time just the one change will not show a difference. I know the non-vvti engines did provide small increases with just one of the three but when you changed all three there was a big difference noted.

Has anyone done this on a VVTi yet?

I've got the magnaflow cat-back exhaust and trueflow cold air intake.Butt-o-meter says there is an increase in power more in 2500rpms and up but still some in lower.I like it,but no dyno tests to prove anything.

Stock is better or just as good for the average guy, 5 hp out of headers if that much wont mean squat, i did headers mainly for the sound to go with my exhaust, do what you like, and think looks cool.

I dyno'd my truck once with simply a custom exhaust. I had no gain in hp or torque. Since then I have added headers and an intake but have yet to dyno it again. I really want to because I am at least sure that i got gains from the headers and probably intake (at least the high rpms)

The butt-o-meter tells me that my off the line power isn't so great, but the top end is amazing! right around 2500 it picks up and at 3000 rpms it really rockets.

Give a little take a litte.....

Only dynos I've seen for the VVTi are on the Unichip site. Not sure if they are actual or predicted. From the two below, the non-VVTi with a Unichip realize some significant gains in Hp and Tq across the RPM band. The VVTi motors are less gain and only at higher RPM. Not what I want for towing and hauling.

Tom

VVTi, stock

http://www.unichip.us/DynoPics/1000271.jpg

Non VVTi, stock

http://www.unichip.us/DynoPics/255.jpg