The twisties are a lot of fun! There is at least one lowering kit available. There may be more now. Get the center of gravity as low as you can. Any added stiffening as in strut braces might be helpful. Look into weight savings. Just taking out weight is not always the right thing to do. You need to look at weight distribution. Take out weight in the right places to help balance the car. As far as things that will help on the road course that are easily swapped out for the track, tires are a great start. Invest in some track only road course slicks and some light weight wheels all the way around. They'll make a huge difference. Also, upgrade your brake pads to a true track pad. Brakes are vital in good track times. The stock pads are a compromise to make our cars more street friendly. I had to change out the brake fluid on my '09 Challenger for road racing to something with a higher temperature rating. I don't know what's in our Hellcats but that is something I'd check into before tracking my car.