You shouldn't need to disable bluetooth on any recent Apple product - their antennas and drivers are very well engineered, and if you can demonstrate a slow down, you could get it repaired (most likely under warranty) since that's not normal. It is good troubleshooting - especially if your router is on 2.4 GHz.
First off, there may not be a problem. If you hold down the option key when you select the Wireless icon in the menu bar - take note of the transmit rate, MCS and other data.
Secondly, you can run the tests with the Wi-Fi Diagnostic that sits in /System/Library/CoreServices to check on the logs, check signal to noise ratio and much more.
If you are regularly transferring large amounts of data, you might need the higher MCS data rates - but it's rare to find a modern router (AirPort, Cisco/Linksys, etc…) that doesn't work very well with Macs. Usually it's an interference issue with spectrum and not that the hardware isn't properly matched. It's hard to tell without doing the work several days in a row to collect network conditions and graphs - but hopefully this helps you decide if/when to get a new router if that's the solution you choose.