Aside from an IRS swap, what significant improvements in fuel economy and performance can be had with removing the adblue and DPF?
Likely not a whole lot, just depends. SCR allows the tuners a little bit more leeway in certain things, because it better allows a diesel engine to do what a diesel engine does best: run lean. Because it is a post-combustion NOx reduction strategy, it lets the tuners use less EGR, which means less fuel use, less DPF regens, which means even LESS fuel use. Granted, DEF consumption may go up if SCR remains intact, but in theory the car could get such a bump in fuel economy that it would eclipse any minor cost increase on that front. Plus, the A7 Golf's DEF tank fill is, by far, the easiest and most common sense arrangement available in any of the VAG cars.
But to answer a previous question: yes, the mounting points for IRS are present on these cars. If you look up on the unibody rail you'll see some extra threaded holes, that is what the rear subframe mounts to. Keep in mind the exhaust system around the rear axle is going to be different too. So a switch to IRS would be more than just switching rear suspension assemblies. There is also I am sure differences in the brake components, specifically the fluid lines as well as parking brake components.
One thing I will say about the A7 Golf is that they seem to have gone
backwards in the mechanicals underneath. The bottom side of them looks much more like the A4 cars, with a stamped steel/welded front subframe and control arms, with compliance bushings once again laid sideways in the failure prone position, and the rear steel twist beam suspension (diesel only). Very different from the A5/6 underpinnings. But the car still feels solid and well put together, and I do not think most consumers would ever notice these changes (which were obviously done to keep costs down). Too bad we only got the diesels for one year here.
But any of you folks fortunate enough to have gotten a 2015 Golf TDI, you have a nice car, I am jealous!
