Congrats on your new bike.
Try some brake cleaner spray on your pads and discs.
Before you think about "mods", think about the "prep". Here are some suggestions:
* regrease head stem bearings.
* replace shock and swing arm bolts with correct shaft lengths (eliminate thread on bearing points with stock bolts).
* replace the "fish oil" in the forks with motorex fork oil. Very important "mod" for decent handling. Copy the original volume of oil if not sure. Try 7.5wt or less in USD forks, and 10wt or more in conventional forks.
* Check your forks are "neutral" in the clamps so that your axle can be inserted by hand.
* Replace the stock brake fluid with some new/real stuff.
* replace the stock rear spring with one that suits your body weight and type of riding. If you are under 75Kg or not riding SX, consider you spring may be too stiff.
* loctite on: brake bolts, plastics bolts, handlebar related bolts, gear shifter lever clamp bolt, rear brake clamp bolt, exhaust header studs and nuts, fork clamp bolts, axle nuts, etc.
* Fit rim lock inside rear tyre and front if want normal pressure in the front tyre too (more grip) without ripping off valve stems.
* Better tyres. Bridgestone M404/M403 rule in most cases. (edit: these seem impossible to get in 14/12" or smaller. So try M402/M401).
* Replace stock handlebars with nicer bend that suits you.
* Replace the engine transport oil with Shell Rimula-X diesel oil. Replace the engine oil at least every 10hrs of run time. Cheap insurance.
* Fit a magnetic oil drain plug. Cheap insurance. You'll be amazed what they catch!
* Light oil (Inox is best) on axles, and generally everywhere metal after riding and washing except the brake discs.
* The china air filters are crap. Get a genuine Unifilter and some of their filter oil.
* Consider adjusting your rear spring pre-load (rear bike height) until you bike turns and tracks the way you want. This can make a huge difference to your fun factor and lap speeds.
* Check your valve clearances. When new if you are keen, then every 30 or 40 hrs. Too tight and your valves can burn and die along with your power and compression. Too loose and you loose power too.
* Consider a Fuelstar TM-VC fuel converter in your fuel tank. For more low end torque and better valve protection.
* Install an inline fuel filter if not standard on your bike. Be sure to position it horizontally so it traps water too.
* Check stock fuel line is not too brittle. Replace if necessary.
* Take your tyres off and be sure no spokes are overlength inside the rims, which will cause tube flats earlier than you'd like. Also be sure to Inox oil the inside ends of all spoke nipples - so they can always be retensioned.
* Adjust your clutch freeplay for easy action for your left hand.
* Adjust your brake levers to suit your right hand and foot.
* Adjust your chain slack (seems to be best checked when someone sits on a pitbike).
* Install a mudflap to keep grit and rocks off your rear shock shaft and spring.
* Learn to adjust your suspension clickers: Compression - your bike ends should each bottom out at one point in the lap/terrain you are riding. If not using full travel then you and your bike can lap faster. If forks bottom out harshly at any place on a track/circuit then increase fork oil volume until this sensation just goes away. Rebound - set the rear so it does not "kick" on braking bumps and/or break loose on accel bumps. But don't go any "slower" on the shock rebound or you will quickly lose traction. Set your fork rebound with enough so that your front wheel does not "push" out of turns for the speed at which you can ride. But do not use more rebound dampening than this - or like on the rear you will lose traction in bumps.
Then go out and flog it to death and you might find your China bike is very hard to kill.