I can't answer as far as the set-up you're considering.
But regarding others opinions of what the SLP set-up sounds like with headers, etc., DO NOT go by what others say, but by what YOU like.
I have the SLP L/T's, Y-Pipe, High flow cats, and Loudmouth, and have received nothing but positive responses from those who have heard it in person.
There are a few sites that offer you the option of hearing them, but I'd suggest researching people in your area and making arrangements to hear the set up in person.
I've been asked on numerous occassions to meet people in my area, and many choose the same set up after hearing it in person.
Remember, its the sound YOU prefer. NOT what others may think.