Probably help your performance a little but maybe not worth the inevitable carbon-monoxide poisoning. <- just kidding!
I also have a 3800, Y87. A fine car. Yes, the turndowns are kinda lame. Is it possible they were design that way because then they could get away without not putting decent tips on?

 

i think they did the turn downs to copy the old styl trans ams. anybody remember those tips?

 

I agree. They just did it to be cheap. If you asked a GM rep he'd probably tell you it was to help distinguish between a Z28 and a V6, but thatd be a bunch of BS. They just took the easy way out.

 

Carbon-monoxide is really only a threat if your exhaust is like that on my '79 Z and ends somwhere before the doors, basically where your feet rest on the floorpan. On a Fourth Gen F-body, 90% of the aftermarket mufflers used are factory styled, which fit just shy of the trunk in a single in-dual out fashioned longitudely mounted muffler. Being that far back, even running dumps wouldn't be much of a problem.

Just remember this "Past the doors, safe for You and Yours' "

 

Cool, I'm cutting my tailpipes off!
I'm kidding of course, but interesting to know.

 

Unless you are hardcore, hehe, I don't reccomend it. Just firing my Z up for 5 minutes will saturate my clothes with raw fuel. I'm also running a rich carb setup too, so that has some to do with it. (No I don't plan on keeping it that way) just waiting for the right exhaust setup.

Most of the people here in SA-Town, are too scared or not equipped to mandrel-bend 3.5" exhaust tubing. If 4" will clear the ground decently, I'll run that.

 

Whats funny is it was one of the head Camaro guys at GM who told me to go get some Z28 tips and put them on. SOmething looked fishy...so I thought I would ask.

 

If you're a decent welder(or have a friend who is) you can do a stock Z exhaust pretty cheap. I was fortunate because my buddy gave me his muffler and tailpipe section off his new 02 Z. I got a new intermediate pipe at the autoparts store and bought a used cat/y-pipe from an LT1 car off here for $20. I was lazy and didn't feel like welding it so I paid someone to do it, plus the intermediate pipe was a one piece deal and I didn't have a lift to get the car up high enough to get it over the axle. It sounds pretty good at idle. It's no V8 but I mainly did it for the Z look because I like their stock tips.