This website seems pretty dead in regards to early-model Monsters, unfortunately. There's another Monster forum that seems a bit more active: ducati monster forums dot org
I can give you my feedback, having recently went through this on my S2R800. The midpipes from 05/06 will fit your '07 so long as you do not have a lambda port (oxygen sensor). If you do, you need to make sure that your midpipes have a bung for you to be able to reinstall your sensor.
Mixing and matching works with varied results. The problem I've found is that each midpipe set has slightly different outlets which results in the different cans lining up in different ways. My DanMoto cans are mixed with DP midpipes and don't line up quite right. I'm sure the Termi cans would line up better. An exhaust shop should be able to cheaply help though with getting everything square.
It's really easy to remap via TuneEcu, but the only prebuilt map you can load for a full exhaust setup is the DP one. In this case, it's hard to say how perfect the map will be for your setup, seeing as it was designed for the termi cans + open airbox mod. Otherwise, you'd need to dyno and tune it.
I've mixed and matched my S2R into a full racing system (open air box + cat eliminator + aftermarket "racing" cans + retuned ECU). So far, no issues whatsoever, other than being nearly twice as loud as stock. The "cat" acts as a second muffler, so once you've deleted that and the stock cans, it sounds like a Ducati-Harley.
Honestly, there's a power difference, breathes a little better for sure, but is it worth $500-$1500? Not at all. Aesthetically, 2000% better. Performance, 5%? If you can get a nice used set cheap, go for it. But, if you're shelling out for new everything... ehhh....
Last edited by _Phaedrus_; 06-21-2019 at 11:43 AM.