What is it exactly you would like to improve..?? What modem are using currently..??
If it is to improve wifi performance, there are better longer term solutions you could try over just swapping modems.
If you are living in a long term residence, moving the phone line/coax point to the middle of your home (if the modem is currently far from one end to to other) so the wifi coverage is more even is a better solution.
Also, you could have a prviate cabler run a network cable from your main modem, to another area of your home and use 2nd router as an access point, and have 2x routers, one at each end of a larger house for better coverage.
Am in a rental, so not in a position to move any cabling. I am using the TPG provided modem/router (Archer VR1600) and have very slow download and upload speeds - testing at my desk (about 5 metres from the modem) is av 20mbs during the day which isn't meeting my needs. I have no signal at all at the far end of the aparrment - about 20 meters from the modem. I've put a wifi extender in about halfway along, but that is getting download speeds of less than 10mbs. Any suggestions welcome.
Can you please Private Message(PM) me your Username/CID/Service address for the service you need help on so i can pull up your account.