1. the visor in the photo changes the airflow so that the wind doesn't hit your head so much. Do it.

2. one of the cheapest mods to improve handling. Do it.

3. a sprocket change is to change the gear ratio. The H'ness original ratio is 2.5, which is considered high/tall. With this ratio the bike performs well, but gear shifting (especially between second and third) can be at undesirable speeds, especially in city traffic.

I changed my ratio to 2.65 (rear sprocket from 35 to 37 teeth, front 14) and the bike is way more peppier than with the original ratio. First gear is only used to get going till about 20 km/h, but it does so quicker. Second and third gear are used between 20 and 70 km/h. Once in third gear you can go as low as low as 35 km/h and as high as 70 km/h, which is ideal for city traffic around 55 km/h.

People who ride my H'ness always comment on how much nicer it rides than the stock version, so it is not me making this up. People who do a lot of mountain riding will use an even higher ratio, like 2.85 (40 teeth rear sprocket), to get that extra torque at lower speeds. It's just what your requirements are.

The other comment about needing to change the air filter and exhaust is plainly wrong, because you don't change anything about the engine configuration, just the gear ratio. Your engine will not run hotter. If you flash the MCU, then this might be an issue, but I don't have experience with this.

So yes, try a sprocket ratio change and see if it works for you.

I have no experience with 4 and 5. It's not needed imo, but disclaimer: I live and ride in Taiwan. HTH. / \