All the cars are very close in times with the same mods but every car will be slightly different. My car likes back back to runs. The best 1st pass with the 3.09's was a 10.55 so for all my testing I think a tenth is about right. As far as driving impressions, if I didn't know the gears were change would I have noticed it, I don't think I would have. I drive mine daily in the summer and put roughly 8k on it with the 2.62 and 8k with the 3.09 I have only had the Hellcat 2 years.
The intakes may only pick with a tweek in the tune like Bmason said .03. My testing same day with the stock and a JLT and stock and a legmaker the stock was faster both times. I also have the stock paper filter in it. I had run a Green filter the 1st year and Bmason tested it against the stock and found the paper was better but for the most part they were pretty even. I know people that say no filter is a tenth faster but I have tested that on 3 different cars, a 6.4, 5.7 and 6.2 and none picked up
Weight rule of thumb has always been a tenth for a 100 lbs but that is at a certain time. Just like 10hp is a tenth which would be closer to running 14's so as you go faster it takes more to get a tenth. I think
@Speedy! was figuring around 30hp in the 9's to go a tenth. It could be more then a 100 lbs in the 9's to lose a tenth. Only way to test weight would be same day at the track and remove it