I know this article is about early s197s but...
I will let you guys in on a little secret.
The V6 from 11-17, the 3.7L cyclone makes about 275 HP at the wheels and many people are still developing the platform even though the engine is dead.
Over the years these people have discovered that the 3.7L may have been a test bed for the coming Ecoboost engines and because of that they love BIG turbos. Don't make the mistake of trying to add a small turbo like the ones on the 3.5. it won't work. But there are 2 companies Auto Mafia Racing and Ortiz Performance selling plug and play big turbo kits.
These kits can safely get you 600-650hp all day on a sealed engine.
Many people are pushing more. And guess what... They don't care because there are literally 100s of these engines lying around and you can find them all day for $500.
So for $500 you can have a car that is faster and cheaper than almost everything on the road. I always recommend a 3.7 for any swap you want to do. It's hard to pass up.
Lastly, unfortunately the 3.7 can't go much past 650hp if you are looking for big power. The cylinder walls are too thin to sleeve. So if you want big power, sleeve a 3.5. if 650 HP tickles your fancy, get a 3.7. If you are a neanderthal that only cares about V8s get a 4.6 or 5.0.
Other fun facts about s197s.
The V6 comes with a 2 piece driveshaft that needs upgraded immediately following any mod. People have been killed because of this crap design. Check YouTube there are videos.
S197 chassis are so stiff, a strut tower bar is no longer needed. Racers leave them in each other's garages as a joke. My car came with one stock (V6 performance package) and I have removed it to save weight.
The stock airbox was designed by Roush. All aftermarket "cold air" intakes lose power. A couple have a net loss of 0, but most lose power.
Don't waste money trying to build an N/A 3.7. The only mods that add power are ported intakes and exhaust. Everything else is pointless. The car comes with 275 HP and maxes out at 300 HP full bolt on.
If you drive a 3.7 and it feels slow it's because most of them come with 2.73 gears designed for fuel economy. Add some 3.31 for boost and drag racing. (It eliminates the final shift before the lights.) Or 3.55 if you want the little extra performance and don't mind the extra shift through the lights.