Well I bit the bullet and had a magnaflow installed with 3.5in stainless magnaflow rounded tips dual rear exit. I had originally planned on going with the flowmaster 40 but after a lengthy discussion with the guy at the shop I decided to go w/ the magnaflow for one big reason...Sincethe Magnaflow actually has sound supression material in it, the sound is not near as loud when you aren't on the gas. I am just fine with this and it seems to me that it pretty much eliminates the highway afm4cyl drone.

So far I have just driven around for a couple hours both highway and city and I absolutely love the sound. It is a little quieter than the 40 series but still has a really nice sound. I'm curious to see how the sound changes after the muffler burns in and I get the cai and tb spacer installed.

As soon as it stops raining/snowing/sleeting/hailing here (KS) for at least a day or two I will get it cleaned up and post some pics and a maybesound clip or two once I get the muffler broken in.

 

There have been a few questions about this lately. Check out this thread:
https://chevroletforum.com/m_58729/tm.htm
Fortunately my truck does not have AFM but I believe it usually kicks in when there is not much stress on the motor which is usually on the highway and at that time your probably going to fast to really get a good listen to your exhaust anyway so I wouldnt worry to much about it. When you are in town romping on it you should have all 8 cylinders cranking thru the exhaust and get the sound you want.

 

Shockerguy08, I have a super 40 i took of my truck and only used it for 1 mile if your interestedin buying it>
PM me

 

I haven't heard any bad reviews about the Corsa Sport exhaust. In fact, due to not hearing anything bad I just ordered one last week. It should be here by middle of next week. I ordered it off Jegs and picked it up for $1,087 2007 Silverado/SierraExtended Cab Std Bed
Crew Cab Short Bed
5.3/6.0L
Dual Under Bumper Exit
Part Number # 255-14199K

 

I will say this! This last summer I disconnected my exhaust from where you would bolt on a cat back just to see what it would sound like if I put straights on it, and at Idle it sounded real good and throaty. While romping on it or cruising it sounded ok. But, the change over which is about a second to a second and a half sounded like ****. Makes you think something is going to fall out of the engine. That's the reason I chose a Corsa exhaust system. they claim to have no drone during the change over with AFM. I'll see and be sure to post.

 

Shockerguy08 I am interested in the exhaust you have put on your truck. I haven't decided on the dual outlet or single with the 4" tip. I have checked out their website and listened to the audio files for the silverado and avalanche. I am interested to know if you have experienced any ab drone in either V8 or V4 Mode in town or highway.

I dont' need anything real loud, just want something that sounds good. I don't want to invest in something that will drive me nuts though, in a month or two.

I had looked into Flowmaster but wanted to go stainless since I live nearby in the "Salt City"!

Let us know what you think.

 

I just finished up my upgrades to my 2007 Silverado Max 6.0L the other day. I put a Corsa Sport dual rear exit cat back system on it and I think it sounds phenomenal. If you are going for the straight piped raspy sounding exhaust it wouldn't be for you. If you're looking for a throaty, sit you back in your seat, and make you **** your pants tone then I think it could be for you. (IMO) But , dont take my word on it. The Corsa exhaust is gonna set you back at least $1100. Truthfully though, you cant hardly tell when you switch over from 8 to 4 or back. I'm also running this exhaust with an Edge Evolution Programmer, a K&N 63 series air charger and a helix power tower plus TBS. I have found a significant change in HP and Torque in between the four upgrades. Good luck to you on your selection.

 

I purchased a FM 70 for my 07 Silverado NBS 5.3 W/AFM and it sounds great when not in 4 cyl. mode. I got the 70 series with one in and two 2.5's exiting with two 5 inch pipes bent at a 45degree welded on. I did some searching and found the diablo u7194 and it turns the AFM off. I bought my directly from Diablo and saved about 60 bucks and they have a free tech support line that is very friendly. The dealership will not turn this OFF.