As was previously mentioned.. perusing the forums will help acclimate you to the different brands. Reading reviews can also help give you a better sense of the quality of various companies' products (that is how I learned about Mugen, Spoon, Chargespeed, J's Racing, Back Yard Special, etc. when I was in the Civic scene).
I would just caution you (but I am sure you already know) to take everything with a grain of salt.. sometimes you may read "reviews" from people who might not have the depth of knowledge regarding what they are talking about (not that they are purposely trying to mislead others), were one of the lucky few to get a quality part from a company that produces "hit or miss" products (companies like Seibon), or are just brand "fan boys". As with every forum.. you should get a sense of who the senior membors are but most importantly who the knowledgeable members are (members like Moto-P).
As for companies that have parts out for the twins (aside from those already mentioned):
RS*R (specifically the sports-i coilover system for the twins.. I remember RS*R more for their exhausts in the Civic world back in the early 2000s).
Toda (produce quality internal components like pistons.. I thought I read somewhere tht they were going to be producing some for the twins.. I know they already have a lightweight pulley kit out for the twins).
Jun (like the above mentioned.. produce quality internal components.. it looks like they have released.. after TAS 2014 it looks like they have/will have an intake box in the works)
Bride, Recaro (mentioned in a previous post.. produce aftermarket seats)
Volk, Advan, Work, SSR (wheels, wheels, and more wheels)
Autofactory (a much smaller and lesser well-known company.. I bought their exhaust and the quality is top notch.. apparently they collaborate with a bigger company Power Craft.. I didn't know of either before I started looking for exhausts.. they also more exhaust components for the twins).
Those are just a few companies out of the bunch. I would also caution you (again.. I am sure you already know) that yes a good amount of the products from these companies can be on the more expensive side.. but that the old addage "you get what you pay for" doesn't
ALWAYS hold true. Just due your due diligence in your research.
Welcome to the forums and enjoy your FR-S
