I was concerned with the stock power on the 2021 700-4 I just bought as well. Pretty underwhelming. I know it’s not meant for speed and that’s not why I bought the 700-4 but it bogs pretty bad on sort of steep hills at 35 mph cruising speed with only me and my wife. I have 27” tires on the way so that won’t help but I also have aluminum 12” wheels coming with the tires to reduce weight over the factory steel rims.
I removed the spark arrestor and installed a K&N air filter yesterday. It definitely has better hill speed now (with factory 25” tires on it still). A little more torque for sure. The factory air filter is so restrictive it’s crazy. Same with the exhaust tip and spark arrestor. Almost like Honda soaked the intake filter media in a bucket of thick grease. It was nasty just handling it during removal. Although it’s noticeably better with the K&N, I know that with engines, any intake or exhaust upgrades really can’t deliver the full potential without adjusting timing and fuel delivery. So I just ordered the Dynojet PV3 tuner to dial it all in. Will also be upgrading to Iridium plugs to ensure good ignition.
Might do a snorkel upgrade as well at some point but I don’t think that would help performance as the factory intake pipe is already pretty wide open and pulling cold air from outside the engine compartment.