Gen6 will probably get FI IMO.
Cheaper, lighter, more efficient and more power. Whats the downside?
Sad but true..
Definitely not cheaper because a reliable, "production" FI engine needs to use more durable materials. Lighter? Not if it uses an iron block. FI engines also tend to run hotter, have very high exhaust gas temps and have lag. Even a supercharger has lag since it takes time to compress the air even though the S/C is driven by a belt.
What a lot of people don't seem to get about the viper's V10 is that it's putting out 640 HP as easily as an econobox puts out 120 HP. That, and it has >500 ft-lbs of torque basically off idle and past the redline.
High revving, small displacement V10, high output - would be fantastic.
I would not have purchased a Gen 5 if this is the kind of engine it came with. The small displacement would kill the torque vs what you get with 8.4L.
Another disadvantage the Viper has, compared to a lot of exotics, is its near 50/50 weight distrobution... It's not going to have the same 0-60 time as a car with similar power to weight, but 60% of its mass sitting over the rear wheels... that's one reason mclarens etc are able to put down such amazing numbers so consistently.
The bottom line is TAANSTAFL, and the more compromises you make to one area to facilitate better performance in another area, the worse overall performance suffers.
Weight shifts during acceleration and deceleration and the gen 5 can hit 60 in first gear, in about 3 seconds. Having balance isn't a disadvantage when you want a car that can do more than simply accelerate quickly in a straight line. It does take more skill to handle a car that isn't weighed down on one end or the other since they're less forgiving to driver error.
The problem is the viper chassis and engine are designed to handle and make 640+HP. Once it is regulated to 500 HP the extra weight in the engine and chassis are problems for it. If you only needed to make 500 HP unrestricted you wouldn't create an 8 liter monster or make the chassis as heavy because you would design both for much less HP.
Perhaps to some extent this is true, but I think you're overestimating the "weight savings" among various engines. Most people are surprised to find out that a 2.0L turbo I4 weighs as much or more than certain 6.0L V8 engines because the turbo engine has an iron block while the V8 has an aluminum block. The V8 also puts out more power and torque without FI.