Had my 19' RS for about a month now and wanted to share some of my observations compared to my '15 GT3 , which I traded in for the car. The 15' GT3 had a rollbar, but was otherwise stock. The RS will be mainly used for tracking and the occasional autocross. Disclaimer: I've only been driving it for 300 miles and haven't flogged it yet.

TLDR; Definitely a more refined ride - everything feels more smooth compared to the '15 GT3.
- Engine: More torque for sure in the mid-range. Haven't hit redline yet, but otherwise the general feel is the same compared to the 991.1 GT3.
- The gearbox at idle isn't as rough - they significantly reduced the gearbox chatter compared to the 991.1 GT3.
- The PDK-S is night and day different. It's so smooth and feels significantly faster. Very impressive.
- Paddle shifters. There is way less travel. Not sure how I feel about this yet. It's almost game-pad like.
- It appears they've optimized the exhaust valve operation in the RS. In the GT3, if you would downshift when the flaps are closed and the lower gear RPM's would exceed 4K the flaps would automatically open up. With the new car, it appears if you downshift when the flaps are closed, they will not open up, even if you're above 4K. This is both good and bad. The good thing is that the car is quieter driving around town. The downside is that the car becomes less loud during normal driving.
- The exhaust sound when upshifting is much better - it comes with the nice "pops" and does sound like a cup car. And you don't have go to 9K to experience that either.
When you downshift at high RPMs the car sounds vicious! An absolute improvement compared to the GT3. But see previous point - unfortunately you'll have to be really on it to experience it. Don't think a different exhaust would solve that problem unless you disconnect the vacuum lines.
- Cabin noise. During normal driving the engine noise is more quiet compared to the GT3 - mainly due to the exhaust valve. But when you're on it is louder for sure. But it's subtle, IMHO.
- Steering. Much lighter compared to the GT3. It feels improved, but due to the difference in feel it's hard to have a solid opinion on this yet. I.e. do I think steering has improved because it's lighter? We'll see.
- Brakes. My previous car had PCCBs and this one has the iron brakes. My PCCBs would squeal all the time. However, the irons with the RS are taking it to a whole different level from day 1! Still need to properly bed the pads in, clearly. Don't really notice the difference in terms of stopping power - both get the job done! Once I take it to the track I'm sure there is more to say here.
- Looks. Obviously way more aggressive. There is much more going on, design wise. I do notice the car sits up a bit higher due to the 21 inch wheels. Also feels there is a larger gap in the front wheel well, but could be wrong here. I moved the spoiler into maximum angle of attack position, which makes the car look more aggressive IMHO.
- Interior. Generally the same compared to the GT3. Different PCM, but I don't care too much about that. I do enjoy that they finally made the audio source persistent. I mainly stream audio over Bluetooth and with the new system I no longer have to manually select the BT audio source when I start the car. Finally! Now was this so hard, Porsche?

In terms of mods, I just installed the AWE wind diffuser and had PPF installed covering the front and wheel areas. Next up will be the GMG LMS rollbar that I removed from the GT3. Should be a perfect fit!

All in all, I've been happy with the car! The car is an improvement in all areas, but it's all subtle. It's much closer to the GT3 than I initially was expecting - this isn't a bad thing. Can't wait to take it out on the track to unleash its potential!

Evolution

Great to read the comparison. Traded in my ‘15 GT3 a few years ago and my RS is finisishing up PPF so hope to experience the same soon.

I don’t like the feel of the new paddle shifters, miss the mechanical snap of my .1 RS. Steering feels almost too light to me.

Nice! Thank you for comparison!
Re. Maximal angle of attack on spoiler, I read somewhere (not sure if I'm confused on this) that you also need to remove some ducting in front dam area to equalize load?

Yup, I read the same thing so I removed those too!