Stay at or below 800rwhp on 93. That's really all it can support safely. That goes for standard HC, or RE.
The recipe is pretty simple, 2.85 Hellraiser pulley, tune, injectors. Make sure to use a well known tuner. Mike@OSTDyno, Curt Dusterhoff, Josh from HHP all come to mind. I run a 2.72 Hellraiser pulley on 93 but it only makes 20 or 30 more RWHP than a 2.85 on 93. I just wanted more for good fuel at the track and it works great there, so purchase according to your intended use. Straight up fast street car stick with a 2.85.
I wouldn't fool with cats or anything like that. Makes the cars obnoxiously loud in my opinion and a pita to pass emissions if you have that where you live. Mine has cats and runs great. HPIndy is a special case as in Canada they get 94 octane and he's using a RE blower so more volume of air on less boost, so not apples to apples for your setup.
The Hellcat motors have shown over time to have a weak area in terms of rods. That's what failed on my original motor. RE engine is supposed to be 30% stronger in that regard, but who really knows. AJ claims no more than 850rwhp on a stock engine whether Hellcat or RE.
I've been on 93 for over a year and lots of pulls on the highway, but never race on 93. I put good Renegade RM109 race fuel in the car for that and bump the power to take advantage at the track.
I've recently started fooling with Flex Fuel and it's the business. If you have E85 10 miles from your house, that's the way to go for sure. Mike@OST setup my Flex Fuel tune and Curt Dusterhoff is known for them as well. It's awesome to pick up 70-100rwhp from a simple fuel change that's $1.53 a gallon around here.