Ye...all of that 100%. Just me thinking aloud here mind, "but" This is my first MultiAir unit as I had no interest in Fiat UK anyway as they consistently hit bottom of the reliability tables in most motoring surveys, it was the "Mazda" connection along with the Italian Styling that won my heart and cash.....anyway, on to the but bit....should I wish to go down the power Super Highway I would NOT do it with the seemingly fragile Multiair engine unit. Yes Millions fitted since 2010 small engine of the year with most of them performing well, if correctly maintained, but once you start playing with this power unit it is clear that it can bite you back, very painfully in your pocket as it was NOT designed to be taken to extremes, so.......Porsche.That's really what it comes down to. If I ever decide to go full send on my 124 with big turbo etc .... I will instead pocket that money toward an LS swap.. I know people hate the "ls swap the world" mentality, but it's the only real way to get large power out of the mx5 or 124 platform.
Of course there are also K-Swap and other options but you'd be 100% on your own making that work. LS Swap has off the shelf options with minimum fabrication required, if you are willing to spend the money.
And while I would love for a "250hp" build to be my thing, I've done that on my 500 Abarth already. I have also replaced the engine, replaced the transmission AND replaced the axles once and about to have to do it a second time. It's back on phase 2 with stock turbo for now, and honestly? It's still making too much power for me to be comfortable fulling giving it the beans on a regular basis. My 124 currently is on Phase 1 with mild mods, and I'm not even sure if I'm going to do Phase 2.
I would be tempted by the 911 but the Cayman really Rocks My Boat Force 9 Style so I would "try" to keep my little 124 Spider Sports car to play with and enjoy still but would opt to purchase "probably" the 2009-12 (a later than 2009 one) model and enjoy the 2.9 flat six unit or even push towards a 2007 era Aston Martin Vantage if I really wanted the power.....So there it is...whilst I love the 124 Spider for what it is I understand it's limitations (Good-Win Racing aside) in the hands of the ordinary gifted enthusiast. Cheers