Hello, I have a GoldenMotor kit, LIFEPO4 battery, 36VDC with 250W motor (PRO902). I love it, the only problem is that the max speed is about 24-26Km /H.
I can do this much with my road bike.

Would be a problem to buy a 24VDC motor and use it with the 36VDC battery / controller to get more speed. GoldenMotor have two versions of PRO902: 24VDC and 36VDC.
This would be the cheapest option as the battery is veeery expensive. I live on flats, hills not a problem (But very windy).
Any advise would be appreciated.

Thank you.