It will depend on the demand. Usually cars that are popular in the auto-enthusiast crowd will have parts released fairly often. Using Mazda as an example, the Mazda3 and Mazda6 are generally regarded as more "tuner-friendly". As such, you're much more likely to see something like aftermarket lowering springs for the Mazda3 over lowering springs for the CX-9. We have a few vendors on the site like JBR and CorkSport. JBR hasn't released anything for the current Mazda3 yet, but CorkSport is usually pretty good about making a healthy number of mods available, usually within the first couple of years after a new model debuts.
Since you posted in the Engine & Transmission subforum, I assume you're after power mods. CorkSport doesn't offer much at the moment (see here), but since the same engine is also used in the Mazda6, CX-5, and the CX-9, you can check out what's available for those to get an idea of what will be coming for the Mazda3. Off the top of my head, I would guess that the Mazda3 would get revisions of the existing air intake, intercooler and intercooler piping kit, axleback (and probably catback) exhaust systems, lowering springs, and maybe coilover suspension. Versatune and Burger Motorsports are also currently working on tuning solutions for the Mazda3 Turbo.
Sorry just edited my post above. Switching to the CorkSport air intake will give you the blow off valve sound, and you should be able to find a decent cabin air filter on Amazon. You can email CorkSport to see if the air intake for one of the other models will also fit on the Mazda3 Turbo.
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