It depends on how involve you wanna get. Both wiring schematics are needed; there is a step-by-step guide if you google it. If you reuse your OEM radio brackets you will have to redrill the mount holes to the Macintosh. If you don't mind the plastic, Metra makes one for the Miatas. When approaching projects like this you will need to think outside the box so to speak. Some degree of soldering skills required. There are aftermarket wiring harness for your car to make the job easier but make sure "you get the Mcintosh's wiring harness/pigtail" when you buy one from eBay. Also get the "US/Canadian version as JDM won't pick up US FM signal unless you decode it, can be done but a lot of work. This may not be the actual DIN size for your Miata so keep all plastic parts of the Metra as you may have to trim one to keep the gap in check if your dash hole is bigger than the Mcintosh which my NA was. Also these babies are not amplified so you will need an amp to run this. Subaru speakers are 4 ohms so the amp and they are low powered so you will have to source out another amp. This will be another project as you will have to match PIN both Mcintosh and your Amp. Pretty straight forward as this has been down many times before. Look up the Subaru forum BTW. Bottom line if you want it bad enough, it can be done. G/L.