This is something I have done a great deal of research on and I have a first gen 3.5 and a 300c with the 5.7. So lets get started, the hemi is way more powerful, however it limits throttle under 30 MPH even with TCS disabled, unless you have a factory scan tool that allows you to place the vehicle in field service mode, or a flash tuner. I like the handling ability of the intrepid, it is far better than the 300c especially in snow. I think the intrepid was one of the best all around cars ever made. It rounds fuel milage, performance, and size, better than 99% of the vehicles ever made at an affordable price range. It's easy to work on and parts are affordable. The 300c will spank it from a dead stop, if I keep it floored after 30 MPH it plants you in your seat, and it pulls like crazy to 150MPH. Now if I hammer down when already moving, a lot of time is wasted waiting for it to get rolling again, it goes really flat for awhile. If you look at performace numbers for 0-60 times ( 2005 300c 5.7 0-60 in 5.6 seconds to 2000 Magnum 3.5 R/T 7.8 seconds )and 1.4 mile times ( 2005 300c 5.7 1/4 mile 14.1 to 2000 Magnum 3.5 R/T 16.0) they tell the story. I usually figure one second is about 5-7 car lengths to gauge bumper to bumper positions on a 1/4 mile run. However I don't have the numbers for passing gear times, the 3.5 should be faster from 50-80 MPH than the HEMI. The new 3.6 pentastar is suppose to be matched with an 8 speed that will get it close to the 1/4 mile numbers of a 5.7 hemi six speed.