Knee protection if tracking with stock seat
 

Any hints from those that track their cars with stock, not bucket, seats?
Of course, there are obvious cons like too high even at lowest and thus limited headroom, and the biggest - limited side bolstering to keep in seat.
It's not as it's impossible to track in stock seats, i just extra keep myself in seat with knees against center console side and door .. problem being, knees from that get bruised and it hurts after trackday a bit. Obviously it gets worse if two trackdays happen in row, as now i need to press on bruises from day before.

Seen these knee pads/cushions for example. Any experience/comments on these or something similar?

Or any hints if side support for stock seats can be enhanced except going for bucket seat & multipoint harness?

Of course, this all might aswell fit in interior mods forum subsection, but imho there might be better tailored responses from those that happen to track also in stock seats, hence decided to ask here.

the 2017+ cars have padded speaker/knee bolsters. like barely-1/4"-thick padding--literally a double-folded towel type padding, but i'm told it significantly helps with this without going nuts on other solutions. just find someone selling used 86 parts of that vintage and see if they've got them available.

They started using those pads at least in 2016, maybe even earlier, as I have them on my car. I can't say how helpful they are because I honestly don't have an issue staying in the stock seat, but I'm certainly glad they're there. The early Porsche Boxsters have seats that are like slabs compared to the ones in our cars, and no kind of padding on the door or the center section, so in that car during a day of autocross or even going for a fun and twisty backroad drive I was having to hold myself in place in the seat and getting bruised up knees like the OP is talking about. I've yet to have to brace myself like that in the FR-S doing the same things...or if I have been then I haven't noticed because my knees aren't getting jacked up like they did in the other car thanks to the padding.

Seeing as the interior of the car hasn't really changed at all since 2012, it can't be too tough to find and retrofit some of those pads that come in the later cars onto ones that don't have it. If the OP does have those already and they're not enough...maybe take them to an upholsterer and get them restuffed with more/better padding to see if that helps?

I have those "thin padded" pads in my 2013-2014 one.
Hmm, restuffing them with thicker/softer material .. hmm, that might work. Those TRD knee pads are RHD only after all, and do close door speaker. I don't think i'm going that much nuts, nor tires are very grippy (PSS level) but track relatively small with many small radius turns/transitions, and "thin" ones hurt knees significantly enough to start think of some "fix" :).
Another idea i thought about, if something can be done to seat itself (idea from browsing this thread about DIY opposite, making seat side bolstering wider to acommodate larger people, where among things he bent upper seat part sides)

Thinking on that more .. i guess moding side bolsters of seat bolsters won't work much, due knees going above them anyway .. due moving seat closer to front to be able reclaim seat back more to gain headroom with helmet on. I guess i should first get 949 racing's steering wheel spacer to reduce needs to move seat that much to front. Modifying seat bottom to sit lower & again adding headroom (with helmet) and also reducing need to reclaim back/move forward under consideration too.
And among other things getting 2016 Camry headrest that pushes head with helmet forward less, though this not related to securing legs/knees.

I have a 2017 and didn't realize the padding was only on newer cars. I haven't had any issues with it hurting or bruising my knees at all, but I have experienced general fatigue and slightly sore muscles the day after especially hard track driving. Guess that means the padding is working if I'm bracing against it that hard.

I love the stock seats but I have started to wonder about moving to one with bigger side bolsters so my legs can do less work. I've also wondered about harnesses that might lock me in better with the stock seat.

Put on old time elastic knee pads. You can get them in colors for high style.
Used to do that in old open wheel as knee kept hitting cowl.

Hmm, adding that as another option to consider. Though will need to browse among available offerings which does best with protecting side of knee. Something is certainly needed, as today made mistake driving 2nd trackday in a row .. and bruises changed to popped blisters :/, certainly not enjoyable with long jeans touching 'em all the time.

Maybe the seats from a WRX will drop right in? I found the seats in a WRX from the same era to be a very similar seat overall, just with more aggressive bolsters on both the upper and lower portions of the seat. Not my cup of tea for daily driving because I kept bumping my elbows on bolsters I wasn't used to having there, and had to really climb out of the seat getting out, but if the stock seat isn't doing well enough those seem like a good way to go if they'll just bolt right in without going to a full blown unapologetic racing bucket.

I'm guessing, that if one is decided to switch seats at all, then one might aswell go for "street-ish" recaros with reclaimable back. Imho as sidebonus potentially one may gain lower seat base/more headroom. STI ones .. how high they sit. By chance not higher then our stock seats?

I use knee pads and they work great. However, contemplating buying 3/8" rubber foam and 3M'ing to the points where my knees hit. I just hate having to slide those things on and off, and remembering to keep them with my shoes.

I have a 17+ w/ performance pack and I still bruise my legs pretty bad after each track day. It's likely better than the earlier cars, but certainly not a full solution.

I've been thinking about hot gluing some small rare-earth magnets to the backside of the factory "padded" center console trim. Small enough where the triangle can be reinstalled.

That way I can make a foam piece with magnets glued to the backside that easily installs and removes without any visible adhesive or future disassembly required.

Something like these. https://www.amazon.com/Neodymium-Mag.../dp/B01LYU3SX8

Gorilla tape and a hunk of sponge. I try not to brace myself with my knees but forget sometimes.