A:
There are other issues that you should make sure aren't causing the slow download speeds.
1. does your modem support the advertised speeds from TWC? If not, time to get a new modem. You can purchase your own and save money in the long run. Be sure to check your ISP's website for supported modem models that support the advertised speeds.
2. How far away are your devices from the router? The further they are, the more degraded the speeds will be. If they are wired, make sure you use quality cables.
3. is your current router up to date? Sometimes a firmware upgrade can help. Get one of your tech savvy friends to help you with that.
4. Did you change the default settings? If not, you should! someone else could be using your bandwidth.
5. Change the channel that your router is using. If there's lots of nearby wifi, that could help. Again, get your tech savvy friend to help you.
To answer your question, NO, this isnt too powerful. It's probably unnecessary though. A new wireless router, not an extender is what you're looking for.