Pete 386 exhaust

[Mrkentee]

2010 386 with single exhaust behind the cab. Support strap broke and my 3 year old $500 stock muffler fell off. Luckily it was close to home. I stopped and picked it up.
I went the cheap way and put a straight pipe in its place. I didn't think it would be too loud, but it is quite loud. It's de-mandated so there's not much between the engine and the air.
The old muffler was straight through. You could look right through it. I bought a universal one for $70, but it wasn't big enough around or lengthwise to fit it right.
My problem is I don't want to attract any attention to myself with this being too loud. They make a muffler insert for $122. Do they work? Will I get myself in trouble, or will I have to shell out for another muffler? Any other ideas? Thanks.