That silver colored motor in the last post with a photo is a brushed 36v 450 watt motor for one of GNG's newer side mounted kits. However I've been wondering if the screw spacing on it is the same as his normal 36v 350 watt motor since I could upgrade to that motor and speed controller along with it if it will fit.
I do not own the brushless kit. I own the 36v 350 watt version that puts the motor under the rear forks (and thereby blocking the kickstand mount) and also drives the main chain instead of having it's own chain spinning the crank's chainwheel like in that brushless kit.
Most of the noise I'm getting is from the gearbox. I suppose the noise won't be anywhere near as bad as mine since it uses a belt drive instead of a gearbox like there other kits.
With my kit the motor drives the same chain the pedals drive. So on first gear I get around 18MPH. I get 24MPH on second gear. There has been one time I was able to hit third gear and that was when I had some wind at my back. I almost hit 30MPH on the thing but ran out of road.
(topped out at 28MPH). Baring any hills or wind, it will usually get me on second gear. First gear works pretty well and doesn't have problems with anything I've hit thus far. I've gone up the steepest hills I can find in my mostly flat town and haven't had problems.
The brushless kit in this thread however runs at 48v and has a higher watt rating, I assume it will do better then mine if the way everything is geared is an improvement. Right now my only issue is that the motor can have trouble with second gear sometimes if I hit a bit of resistance. My rear freewheel has a 34tooth first gear, but second gear is only 22 teeth so that's a bit too much of a drop from first gear. I found a new freewheel online that has a a 28 tooth second gear and should have a much better transition from first to second. But it's a bit pricey at $44 so I plan to save up before buying that.
Aside from the sidemounted kits having weak mounting brackets, the rest of what I got from GNG seems to hold up well for me. I used the same motor and upgraded it to a mid-mounted system since GNG was nice enough to sell the mounting hardware for the mid mounted kit separately so I didn't have to buy a whole second kit just for the mounting hardware. Motor still works fine after putting nearly 600 miles on it thus far. So I'm to assume his other motors will at least perform good at their rated power levels. I haven't dissassembled the motor or anything so I don't know how the motor is built so as for thermal performance....don't know. After a maxing out the battery range at 10 miles on a non stop trip, I felt the motor. It was hot to the touch, but not enough to burn my fingers and it didn't feel like it was hot enough to melt down or anything. I've noticed the heat seemed to be greatest on the rear panel of the motor(where the brushes are I assume). So I'm guessing that is where the motor windings are offloading their heat to the rest of the motor frame. Not to mention the gear box is probably adding some heat to the mix as well.
But I don't have the brushless one so unfortunately I can't say how that one will perform and how well it would work if one would over volt or go beyond it's rated wattage power.