Transmitter power output is restricted so I doubt you'll gain range by shopping for more. Besides, sending a voice modulated carrier into the atmosphere is the easy part. Key elements for clear communications are a high quality receiver, transmission line and antenna.
I'm sure the above recommended transceivers have excellent receivers so you might consider an external antenna. This antenna would most likely mount on the top of the aircraft where a proper ground plane would provide better gain and directivity, and could be easily plugged into your handheld. This antenna would require a 6 foot long or less transmission line with a proper terminating connector to be accessible in the cockpit. The quality and proper installation of this termination is critical for good performance.
If an external antenna won't work, look for optional higher gain antennas for your handheld. They'll most likely be longer and should be held vertically for best results.
For cockpit noise consider external earphones. These would greatly reduce the noise and give clear received audio. On the transmitter side you might ask about noise canceling microphones. These microphones are designed for noisy environments such as yours and may be available in GA
band transceivers. Check the instructions to be sure that you are talking into the microphone properly.