Pista's exhaust tube is the easiest way to go. I am surprised someone hasn't started selling those yet. In M-B world, a guy sells a similar exhaust tube w/ flanges to bypass the problematic catalytic converter used only on 1985 CA diesels, which is a very small market. Slants were in vehicles for 2 decades. I bet many truck guys would like a turbo too. I doubt a turbo would improve idle or driveability, since it doesn't contribute much until >2500 rpm. I think the hope of better mileage is unfounded. Mileage comes at low throttle. There is no advantage in boosting the pressure just to throttle it back down. In cars, the mileage comes from allowing a smaller engine to give higher HP when needed, so by letting you be happy keeping a slant saves gas over converting to a 440. In diesels, a turbo does improve mileage since they have no throttle. The recovered energy goes into the input.