You guys make very fine products to say the least and I would have some if not for DIY what I needed prior to your offerings being available.
My recommendations are based on real world experience and what your business model appears to be.
Great requests here, some may not be viable as you need to sell enough to make the investment worth your while, totally understandable and you have your way of doing things, many parts would require a lot of outsourcing and not be as easy to control supply, etc.....keeping to what works for you is most likely the better path.
REM, rear engine mount, that is less harsh would be cool (our cars are engine powered, not motor powered, the whole industry is lost on that one
Though another company, as mentioned, is making engine mounts not a bad idea to have competition.
PEDAL covers, stock one not so attractive, that correct for heel and toe, and match a dead pedal, that would be great
Shift knob that does not burn your hand, ties in with the pedal and stock steering wheel style....
Bolt on support for front sway bar mounts as they tend to crack, might be a bit tough to work out so a worthy challenge
REAR CAMBER shims, another serious part that would take some effort to work out but would help the car be more stable on high speed corners, the stock setup is for slower speed fun, some like to go faster than that. Might not be enough market for them though.
Though trick manifolds and TBs look cool not that much needed, how about, as mentioned I think, manifold spacer with port injectors, or your current spacer with 8 injectors, etc...so all the valves can be kept cleaner.
If you do chassis braces follow the lead of what I believe only one company so far is doing, test them to ensure they do something besides add weight and placebo effect and make them for where needed, not just whatever will sell even if stiffer but not really needed. (almost always a stiffer chassis is better but not if the whole car is not taken into consideration.)
Your shifter seems to be an exceptionally well made part and I would of bought one to try if I had not done a DIY already. You can make a less costly option, not as overall refined but still helps those on a tighter budget, with a simple kit to raise the whole shifter base assembly, I sent you info on that a long time ago.
This one is a bit harsh but until proven wrong which I doubt will happen....
"Wing risers" when the car does not even have a wing, it has a spoiler and raising it is a bit of rice unless aerodynamically enhancing which is highly doubtful, likely it just upsets the wind tunnel designed aero on this car, not a fan of it
Sorry for that but I just had to say it as it has bugged me since day one
I have many other ideas but they do not fit into your profile so not posting them.
Good day!
Rick