Alloy boy
There are some advantages to alloy parts.
For example, the standard front pulley gear is plastic, when a 3rd party alloy front diff is used, the plastic front pulley gear will break.
I use steel dogbones on mine, even alloy front bones are too weak to put up with the strains of a 300 sized motor.
The weight gains are marginal and serious racers usually end up using small lead weights as ballasts to get their Micros perfectly balanced.
The one part that blows my mind is the alloy X-Shock kit, this doesn't work at all unless you are prepared to do some serious re-working on them. Just another typical GPM non functional hop-up. So many people buy this part and end up removing it!
I race my Micros often and I agree the standard chassis is the pits. It's great for driveway use, but any serious Micro racer junks it and uses a decent 3rd party chassis.
On my two race Micros I use Penguin P3500 series chassis, these have an amazing roll-plate based suspension system, with up to 16 settings on the rear end.
Thad Garner, who has won most of the HPI Micro challenges uses a Penguin chassis, he is also a HPI sponsored driver.
My third Micro which will run a Graupner Speed 400 Race motor uses the cheap & cheerful ARM pan chassis, this car will be more orientated for straight line speed and not racing.
Perhaps you guys need to take a look at
YourMicro to see some of the custom chassis Members have made.
Let's not forget "AktionDan" Marx's amazing 540 hybrid Micro.
Bottom line: Out of the box, the Micro is nothing more than another cheaply made entry level RC car.
If you want to make is raceworthy and reliable, be prepared to spend some serious money on it, in the right places of course.
And the only standard parts on my Micro are:
Front suspension assembly and lower bulkhead
Rear bulkhead
Inner wheel hubs and wheels
Belt
Diff shaft
Screws
That reflects just how much room for improvement HPI left on the Micro RS4.