I have a Fischer Panda 4.2 on my H33. Gives the boat a slight port list. I have sailed on a Catalina 30 with a Northern Lights Genset also gave a slight list. What is your budget, your looking at between 12 to 15 K. It is nice to run the AC when motoring or sailing if you need to. You will still hear some generator noise.
The Fisher Panda is the cleanest install, it is in a noise reduction shield. I think 4.2 is the smallest, did you find something smaller? Don't forget about the overboards, strainers, exhaust, wiring, fuel system.