Looks Good! IIRC, there is a pop out panel on the SK rear fascia. I noticed it when installing my rear hitch.
One other question - do you want this just for the look or are you expecting some type of improvement in power due to less restrictive exhaust? That latter part wouldn't be probable because you're still limited by the single junction as left side and right side exhaust comes together.
The reality is as far as exhaust fow, it will be
slightly harder for the engine to push the gasses out of a dual exit set up. (Assuming the split is the same diameter as the pipe feeding it)
The added volume of the split will slow the velocity of the gasses in the pipes. The higher velocity gas coming out at the split will run into the slower moving gases in the split.
"Less restrictive" can be an illusion if just going off of pipe diameter. It's all about velocity. Too large of an exhaust system can actually create back pressure because the engine has to push the larger volume of air out of it's way.
This is more of an issue with N/A engines, and not so much with turbocharged. The pipe sizing there would be on the ridiculous side once it became an issue.
But for this application, I doubt it is going to really make a difference either way. Ideally though, the Y split tubing would be slightly smaller than the feed pipe to the Y. That way the velocity of the exiting gases is maintained.
Also consider the gases cool the farther away from the engine they get, further slowing them down. That's why a lot of oem exhausts get slightly smaller as the pipe gets to the rear of the vehicle. They design it so the gases keep moving, for the best fuel economy.
Considering the amount of power that is put out, given the relatively small piping compared to yesterday's cars, it's obvious the engineers have done their research. The power is more than double, even triple in some cases 1980's 4 cylinders, and the exhaust pipes are the same size or smaller.
