Good point on the tires but I would image most here run some sort of all seasons. They are definitely the most important in all aspects (handling, MPG, stopping since it is the only thing touching the road)! But I will disagree about the dive. The OE spring rate is not high at all.
I do agree the stock brakes are OK, especially if you are driving solo or light load. It becomes an issue when you are loaded up, and compounded if you had to make multiple panic stops. After the first-second hard stop, brake fade becomes noticeable (better pads would help) but there’s more. This was experience in my GT with brand new Mazda OE pads and 6/32 Touring-AS tires loaded up with 4 adults, 2 kids, and bags tucked all over. For day in/day out, the stockers are ok. Also none issues if you are the gradual braking type (safe following distance) and hope to never run into any panic/emergency situations.
I would not call the MS3 brakes a big brake kit, not even close. BBK’s run well over $1k and utilize large pistons or multi pistons. For the record, both the Mz5 and MS3 calipers have the same diameter pistons. Per MS3 owners, they also clear 16” rims. It is simply a nice upgrade for little money like how the MS3 RSB improves the rear end. Not earth shattering but a noticeable and welcomed improvement for very little money (effort in cost is a different debate). The upgrade is only cost effective if you have the need to do pads and rotors and means to DIY, otherwise it would be not be cost effective but then again OE rotor really do suck so your call.
I don’t believe the benefit lie in slightly larger pads or rotors, which obviously help. Assuming all things equal, what the MS3 calipers provide is the extra large surface area in the caliper bodies. Looking at how the floating caliper design works, you'll notice the Mz5's is quite small. Here's my interpretation on where the benefit lie, do excuse me if my example is not so good as I’m using an extreme to illustrate a point. Imagine taking your two hands and straighten all of your fingers and on the tips of each hand is a pad. Image if there is a spinning disc in the middle. Imagine trying to stop the imaginary disc from spinning by pushing your finger tips together (against the pad, which goes against the disc). Now imagine all things equal (same rotor, pads, tires, etc.). Having the MS3 caliper bodies are akin to using your palm to do the same thing. The amount of force you apply pushing with fingers or palm does not change. This is the benefit, particularly brake feel/confidence you get. I hope this makes sense.
My main point is share there is very good benefit from this upgrade. I'm not promoting it since it invovles your time and money and we all have different priorities in our lives. It is something to consider "IF" you need new pads AND rotors and capable of DIY. Be safe.
Thanks. I will have to look into that spare.
Like all things in life, there will be trade-offs. I'm at a point where I value "quite" and "cargo space"
but
so GT-AS is the category for me but man the tires in this class are pricy.
