First off, the aluminator is a $9200 modified Coyote crate engine. The Stage III kit would add $7300 to that, not including shipping and installation. It would probably require other upgrades to beef things up. I read the article a while back, and think they got their facts mixed up. The picture they show is not a RS. You are not going to get the same power from the V6 as they get from the V8.
If you start with a 2014 GT, the Stage III Roush will be about $18-20,000 on top of that to get a factory job. In the long run, that would be the most practical way to go. FYI, the Stage III w/o the aluminator upgrade will only go to 575 hp. Before you go too far down this path, I would suggest that you try driving a Stage III if you can. I know people that have them, who are serious racers. Those cars never come out of the garage other than for special occasions. They are just too much to handle for day to day driving. There is no room for error. With a commercial turbo/super charger unit that is available for the V6, you will be able to put out 450-500 hp.
2013 MCA Edition-Sterling Grey
Roush body kit - Splitters/hood scoop
Whiteline suspension w/Koni shocks