not to farfetched. I think Dirt Fish Rally has driven a rally version of an ecoboost. they definitely have a lifted BRZ too that they throw around in the dirt all the time.
Do it. I've been thinking about how fun a rally S550 would be. Get some good, trophy truck quality suspension under it and tear it up. Sounds like fun.
Took some measurements today and looks like this isn't going to happen. Can't even up the tire radius 2 measly inches without hitting the wheel well and there's no way in hell I'm cutting or rolling the fenders. Largest tire you could probably fit in there is 255/50/r19 or 29 inches before things start rubbing. That will only give you an extra 1" of ground clearance. Might not even be worth it to try to put in 3" coil spring spacers if you can't even clear the tire front and rear.