You have some excellent points, accompanied by the ideas and want to get some performance from the V6. But the problem isn't just that some of the parts aren't made (no one offers a bigger t-body for the X, but a 3.5 might be larger, don't know for sure), it's that 99% of the X's on here are the daily drivers.

They have to maintane the driveability, reliability and retain the emissions of normal vehicles. Lopey idles with the kids in the back seat isn't usually what one likes to have.

No aftermarket intake is available. Unless someone gets theirs extrude honed (hard to get done right, and without other upgrades, can be a dangerous mod) and then dyno tuned with the full aray of tools and equipment then they won't really see the benny of expense.

The MAS (we call 'em MAF{Mass Air Flow}) is actually plastic, not encased in metal. So getting another unit in there could be tricky with the computer having to be recalibrated.

All in all though, good ideas. But the daily driven aspect of the majority makes it less feasable at the moment. When these trucks get older, and they're the 2nd vehicle that's just for fun (that's what mine is for, the Frontier is the Daily Driver), then you'll start seeing the mods take shape.

When I blow my first motor, then I'll take the extreme in account. Take the psi of the pump up a couple of notches, flow the heads, dump the cats for some normal units (to facilitate the headers) and so on. But thats a ways down the road.