I just looked up your scoot..it is indeed a liquid cooled, 2 stroke 50cc with rear disc! I wasn't aware Kymco made a liquid cooled 2 stroke. A little confused by one of your questions...you already know the VIN, you posted it (it's a unique number assigned to your scooter). That's your VIN - vehicle identification number. You also know the model name..not sure if Kymco also assigns a model number?
It seems like every other post in the 50cc section is about making the scoot faster, quicker, etc. No disrespect, but if you want a faster scoot just buy one with a bigger motor to begin with (a 125 or 150cc).
Your 35-38mph top speed is pretty impressive for a 50cc scoot. Seems right where it should be. For bogging issues I'd make sure your carb is thoroughly cleaned, to begin with. Make sure your rollers and belt are all in good shape.