I would seriously wait until he at least posts some dyno numbers. Personally, I'd wait to see what the long term reliability and durability look like. A .090 over bore is pretty big (.060 isn't small, either). Cut the cylinder walls too thin and you're in for a world of trouble. You're also increasing the rotating mass, so I'd be concerned about the long term effects on the bottom end. The 3.8 wasn't designed as a powerhouse.
Simply increasing displacement and adding a cam isn't doing a whole lot without the other supporting airflow and fuel mods. Claiming supercharged torque numbers is a BOLD claim. Ripp claims 240 lb/ft of torque with their kits, over the 180 lb/ft baseline. 60 lb/ft of torque from a bump in displacement and a cam, with no other air or fuel mods? Without porting the heads and the intake, I can see a modest increase down low, but I'd bet it falls flat on it's face higher up the rpm band. For the money, that's not a good trade off.
I don't see any mention of what the stroked displacements are, or even what brand parts he's using or the cam specs. That's important!!
Increasing displacement increases power POTENTIAL, but the rest of the engine needs to be able to supply the added air and fuel to make more power.
I'm no expert on the 3.8, but I've been a hot rodder for long enough to ask are the heads and intake REALLY up to the task of making his claimed numbers possible, with a simple bump in displacement and a cam?
Forced induction is different. Pressurizing the cylinders makes up for a lack of airflow. If/when you increase airflow on a blown engine, you see that much more gain than you would n/a.
I'm not calling shenanigans or anything like that, but they're trying to sell you a stroker kit (and not a cheap one at that, but seeing as how there's not much of an aftermarket for 3.8 internals...) with no dyno numbers, no long term reliability data and no mention of actual displacements or parts used. Personally, I don't like being a guinea pig. Not on my dollars. Coming from the hot rod world, you gotta prove it first.