On suspension I would try something a little different. Stock, these cars have too much understeer. I would go with a little wider front wheel and 235 tires. Voughtland springs and Koni shocks. Leave the front sway bar as is. Go with a little wider rear wheel with 265-275's. If the car is still pushes in the corners, then add a larger rear sway bar. Another thing I noticed that really helped handling believei it or not was really big brakes and a bunch more torgue and HP. These two things added together allow you to easily control weight transfer into, through and off the turn. If you are serious about the twisties, get the paddle shifters if you have an automatic, it is much easier to keep the engine in its sweet spot at all the various speeds.

As far a power goes, Obviously, I believe in the old saying that there is no replacement for displacement. At 53 I must be an old guy as we never really had access or much interest in a dyno. for us the ET was the dyno. We measured in tenths not hp. Dyno's don't take into consideratiion weight of the car. aerodynamics and suspension or driver ability. If I had stayed with the V6, I would have picked up a 3.7 out of an ML dirt cheap swapped it in on a Saturday, I then would have worked on the mods listed above as well as delete the socondary CAT's to let it breath easier and then added boost or NOS. On my 5.0, I did AMG intake, screen and bafflles, 55 n/a cams and secondary CAT's. These mods made a very nice inprovement to the top end performance. Keep in mind that you could achieve a higher HP number on a dyno and make your car slower in the 1/4 mile becuase you moved your torque curve up. In my case I had an abundence of low end torqie, but was lacking on the top end. The mods i did increased the top end but sacraficed some low end torque. This worked well for me because I had more low end than I could get to the ground with the V8.