Will you get more ponies and better sound having the Bonneville Gxp stock exhaust and add Magnaflow mufflers.

You'll get different sound, but I don't think changing only the mufflers will increase HP any.

GM engineered that exhaust flow pretty good.

The only way you'll see any noticeable HP increase is if you do a full exhaust. Even then, it won't be any major increases.

The mufflers should give it a nice sound though.

fyi changing out any of the stock exhaust with aftermarket parts, converter, pipe, mufflers etc will lead to an always on check engine light......the exhaust on these puppies is very timid.....and the computer hates you if you change to aftermarket parts

That'* incorrect. We have plenty of members who have changed out exhaust parts with no problems.