advance

I was close to getting the atomik then saw people saying they break easy, I see gmx 70cc from Australia, or the 90cc pitpro towards the pitpro. Are there any better options out there or is the pitpro the way to go? Thanks in advance

I have had this bike for over 15 years and would like to put in a lifan 125. Any suggestions or advice on what else I will need to change when doing this? Thank you in advance