It all has to do with your preference in engine technology, and in this case, a choice between rev-happy natural aspiration and the low-end torque of forced induction.
But the differences between the Mazda MX-5 and 124 Spider can be found in other places as well, as explained by Esteban from Redline Auto Parts. No fewer than seven minutes of video detail a pair of rolling drivetrain chassis, and as you can tell, the rear differentials and Bilstein shock absorbers are particularly similar between the two.
Different spring rates and gear ratios are to be expected, but the Miata sweetens the deal with a diff dampener the Fiata doesn't feature. The limited-slip differential is connected to a six-speed manual in both cases, and if you look closely at the bell housings, you'll notice the Abarth features the three-pedal setup from the NC while the ND comes with the new tranny.
The motor mount brackets are specific to the Abarth, and the front subframe also makes a discordant note with the curved portion that makes more room for the intercooler of the 1.4 MultiAir turbo four-cylinder engine. The packaging is another affair altogether, made more difficult by Fiat because forced induction always adds complexity to an engine. The SkyActiv-G 2.0 happens to be longer, but nevertheless, servicing is much easier.
Want to talk about pricing and output? Let's start off with the Mazda, which starts at $25,730 before delivery charge for the Sport trim level. That's pretty good value if you take into consideration the G is good for 181 horsepower and 151 pound-feet of torque from the get-go, don't you think?
$25,440 is the starting price for the Fiat version of the 124 Spider while the Abarth is $29,540 excluding destination. The most potent tune available for the MultiAir is 164 horsepower and 184 pound-feet of torque, which is a tantalizing proposition when you think about it.
Which would you pick if you had a budget of $30k in your pocket?