that is quite the time difference. 3-4 seconds is years when talking about lap times. On a totally unrelated note, I want that spoiler, could be little wider, but still.....

The difference is likely mostly tire.

17' PP Michelin Primacy HP, 215/45R-17 87W
18' TS Michelin Pilot Sport 4, 215/40R-18 85Y

You cannot gain 3-4 seconds just with tires. The race track is not that large.

Where did I say that? And it is a large track.

Just an FYI but there is a 2ish second difference over a 2 minute lap within the 200TW tire category. You think this is not possible going from the Primacy to the MP4S over a 3+ minute lap?

Pfff... BRZ tS has the PS 4 tire. Not the 4S which is more advanced.

The tS had chassis stiffening improvements. Not only with the flexible stiffeners or other bolt on parts. Even a modified BRZ wasn't that fast. These have been tested at least a year ago.

You'll make the most gains in better lap times with good coaching combined with seat time.

Yes, chassis stiffening makes a huge lap time improvement. Where is our rolleyes smiley? :D

Chassis stiffening can help factory to improve suspension settings and provide on same tires more grip or on a slight sportier tires like the PS4 a quite good result. My point is that it is not always that simple to go just with grippier tires and improve the times. You will gain some time, but after a point you need more changes. One change affects other parts on the car. As mentioned before in this thread, this is not a usual Civic LX or a 2001 Neon sedan that will give you the same sort of improvements.

You can gain more from camber bolts and a zeroing the toe then all the STI parts in Subie’s catalog combined. Chassis stiffness is not the issue with this platform.

Just save money for other things in your life and enjoy the car as is. After years of modding I sometimes think it is a disease, always looking for that improvement that is so subjective. I really wish I could buy two cars and leave one stock so I can compare side by side.

My disease is terminal, save yourself............. :burnrubber:

If you look at the two videos, the 2017 entered the back straight at 60 mph and reached 110 mph. The 2018 entered at 61 mph and reached 111 mph. Based on those numbers, the 2018 had no power advantage over the 2017. To me that means the 2018’s 3-4 second better time was related to a combination of a better driver, track conditions on that day, tires, brakes, etc.

I consider myself semi-conservative in that sense. At the beginning I got pretty excited, gotta admit. I was trying to buy everything, but that's where this forum came in handy. Tons of info and research, so I got what I truly needed, plus little extra things that I just couldnt resist. Fully understand that unless I go FI or SC, no matter what extra things I add other than UEL headers and tune, everything else will be a subjective gain in power. Which I'm fine with. Car sounds nice, feels nice, looks nice, and I'm happy with it.

Catless headers and E85 have been shown to provide the most significant (double digit) gains.

A 4.67 diff will increase wheel torque by a further 15% to make a very quick NA car.

Compared to these, other bolt-ons offer insignificant gains. See dyno day charts from Shiv at Vishnu performance.

If you have no access to E85 and need to retain cats then I highly recommend a lower ratio diff for spirited daily hooning.

And, as others have alluded to, don't ruin your lovely car by modding the shit out of it unless you're chasing silverware.

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