Hey Scotty, I just recently bought my first car, a 2005 mazda miata with a 1.8L naturally aspirated engine, and I have a two fold question

first, the car is well taken care of and the engine sounds and runs great! However, it has 146000 miles and only 5 gears on a manual transmission, and the way the gearin is set up I'm pulling about 4100 rpm at 80 mph on the interstate. It has a 7000 rpm redline, but I wanted to know if that high of an rpm would end up damaging the engine over time or increase wear at an alarming rate, is there anything I can do to combat that aside from driving in the right lane? Also along the same vane, I plan on turbocharging it at some point in time. It has 10:1 compression, how much boost would you recommend if any at all?

supercharging it is a much better option, they have kits for miatas. As for gearing, those are just geared low for bottom end speed. The faster you go, the faster engines wear out, but 4100 hurts nothing

Thank you!