Bingo!! Very good info here.
I myself am building a very budget friendly exhaust for now till later down the road when I upgrade to the TVS.
For now my budget M62 exhaust will be GM extruned honed mani, modified stock dp with exit flanges changed to 2.5, LNF cat back exhaust.
In total I spent $130 bucks for basically a stock appearing, hopefully stock sounding 2.5 exhaust. I have heard some say the LNF muffler is to loud and raspy for the LSJ, but I'd like to hear it for myself.
If so I'll just open up the stock LSJ muffler to 2.5 and put it back on
I ran an LNF cat-back on my RL. It's "Okay" at the best but I would not recommend it. The LNF resonator is shorter then the the LSJ and the LNF muffler is not as quite.
I even replaced the short LNF resonator with a 24" Smooth Tube muffler from Stainless works and it did not make things much better.
In your case, if you really want to try out the LNF muffler for yourself you could buy an LNF flange from ZZP and have that matted to the your stock DP. The inlet to the LNF resonator is ~2.7" so it will be nice and free flowing.
Then be prepared to replace the LNF muffler.
The cool thing about the LNF cat-back is that is it 2.5" ID piping from the resonator to the muffler. The LSJ is 2.5" OD. But the nice thing about the LSJ piping is that you can install the 2.5" v-bands much easier because they are 2.5" ID. Just clean up the edges with sand paper and slide it over the end.
Then take it to the exhaust shop and have them weld it.
Here is what my LNF experiment looked like.
Metal Spun Cat
24" Stainless Works Smooth Flow Tube Muffler. 3" inlet 2.5" oulet
It did not sound that great.