I have a 2008 Mazda5 Touring with 232,000 miles. Original engine and transmission. Went through multiple engine/motor mounts. Last week, I just replaced the NGK iridium spark plugs as one of them cracked. Oil leaked through spark plug number two causing a cylinder misfire. I ended up replacing the coil pack plugs only as the oil messed up number two coil pack plug as well.
Overall, everything is original except for the normal maintenance item. (Tire, brake, wiper, etc). The only major replacement items I had were the transmission control module failed at 140k, oil pump seal failed at 160k, and a radiator cap at 200k. The suspension and mounts are clunking, I just live with it as it is a 232,000 mile car.
I've added items such as a roof rack, LED headlights, backup camera, led interior bulbs, Bluetooth cigarette lighter, nothing fancy, but just functional.
Overall, this is a very reliable car. I've been on multiple vacations with this car on dirt trails and all. The 5 is a very versatile car, what I call the Swiss army of cars. Fun to drive, yet carry passenger, cargo, and anything you could throw on the roof.