The only way he noticed the donut wasn't sealing is he was taking a few rips with the hood off while checking a few things and saw the pipe moving under throttle. He used tie wire to hold it nice and tight and it ran perfect.
Rode last week with a pro giving very similar issues, tried most everything to fix it, found it was the donut between pipe and y was trashed and springs were not holding a tight seal. Full throttle was opening up drawing air in. Try some high heat silicone and new springs.
You cannot change a 2 watt rino to 5 watt. What you buy is what you're stuck with. You can buy on eBay from an American seller and get the 5 watt radio shipped to Canada. But beware, if you have to get warranty work done Garmin Canada will send a 2 watt radio in return.
Yep, 4 will fit in a 20+4. We've put 4 in a 16+Vwith some stategic planning.!.. We put two in frontwards with one right in the nose then split them apart. then load next 2 in backwards with tails in the middle. Tight squeeze though!