Fullsac no longer offers a 2.5 baffle. His offerings are 1.75, 2 and 2.25.
Fullsac makes a good headpipe for the M8 and you can use factory heat shields.
Hey Dave, he has a '16 so TC not M8. However, you are correct in Fullsac making a good headpipe for the M8 and TC.
groupw, if you don't want to spend the money for pre-fabricated items from Fullsac, V&H, Bassani, etc., you can go less expensive in decatting your stock head pipe and removing the plugs on your stock SE mufflers. If you are good at cutting/welding, the catalyst removal would be just your labor. If not, you can find the headers decatted for about $150 (give or take $25) from either your dealer or a good muffler shop with your stock header as a trade. Removing the plug from your stock muffler is just as easy even with the extension the MoCo put on them in 2014. Here's the link to my thread from a few years ago with lots of information on how.
https://www.cvoharley.com/smf/index.php?topic=74847.msg1027930#msg1027930I'm not trying to talk you into either option. If I had not gone the do-it-yourself route, Steve with Fullsac would have my money and his product on my '12 and on my '15. I like to tinker and fiddle with things and, for me and some others here on the site, removing the plug and catalyst was the way to go. I like the stock look so doing it myself was a good option. Steve also has designed a great header so you can utilize the stock heat shields but it's a bit more money out of pocket.
On my '12, I went with the SERT on the decatted header and deplugged mufflers and a dyno tune. I did the same on my '15 with the exception I went with the V&H FP3 tuner and tuned it myself. I did remove the 3" pipe extension (two tack welds were no match for the Dremil) soon after I got the bike home and long before the exhaust mods mainly because the extension was rusting and causing a mess. As for the results, I was very happy with the power on both bikes. If I were to do it again on another TC, I'd go with the FP3. I'm not saying there won't be another HD in my future but it won't be new and I'm not sure it will be an M8....better the devil you know...
If I had gone the Fullsac route, I would have taken Steve's advice and used the TTS tuner since there are maps specific to his header/muffler set-up.
Review all the threads on the site cause there are MANY opinions on this subject. Some hate this, some love that, some would rather eat a dog turd than have XYZ item on their bike....it goes on and on....so good luck on reviewing it all, evaluating the good/bad/ugly of the choices and making your own.
Keep us posted