I've also done the mod. I am waiting for some time next weekend to take apart the center console to bring up the boot cover (the knob itself is shorter, so there is a gap) and also to replace the boot with nicer looking leather one, courtesy of Overland Designs.
The knob is very nice. It's a good bit heavier than the comically light stock shifter but it's not ridiculously heavy. I think 300+ grams is overkill.
I really wish that the car came with a heavier shift knob and shorter throws on the Mazda 3. I'm learning to live with the wheel gap (it really doesn't bother me once I start driving), the 4-5 shift always feels a bit awkward but the front-to-back throws have been taken care of by the Corksport short shifter plate. Highly recommended mod.
My next functional mod will be the Progress rear sway bar, set to soft (but still a good deal stiffer than stock).
Love the leather shift boot I got from Jason at Overland Designs. I asked him to make it 1/2” taller than stock as I used 5/8” worth of galv metal washers inside the top of the boot to rise the height of the shifter knob. I send him the OEM pattern for our current gen Mazda 3’s, and so he is all set to make more of them.
If anyone wants him to do the same, just tell him you want what he made for John from Oregon.
Or if your lazy like me lol take some electrical tape, wrap it around the spot where u want the boot moved up, squeeze the boot up and over. That is exactly what I did for my ND Miata shift knob mod and not a single issue since. Fits perfectly and hasn't dropped down at all. I like the weight, and it feels great in the hand, definitely a very worthwhile mod with an OEM feel to it.