The 'debaffled pipes cause warped valves' is a classic example of a small amount of truth warped into something else. It's because people don't understand the ROOT CAUSE of the issues.
Warped valves can be caused by cold air being sucked back into the exhaust and hitting hot valves. The stock 900 exhaust is way too long to ever do that, besides, it has a cat converter still in there, so even a full debaffle isn't 'straight pipes'
It's one of those causes of basic observation without asking the important 'why' question. Billy Bob the Racecar Builder noticed his open-header racecars burn valves. He knows open headers provides more flow. So he determines, straight pipes or high-flowing exhaust will burn valves. The real reason was because A) he was racing the darn thing B) likely the mixtures weren't great and C) cold air could have been sucked back up through those open headers hitting hot valves, especially on shutdown, causing them to be warped. That's why engines where longevity is important (like NASCAR engines that have to go several hundred miles) you'll find straight pipe exhaust, but an engine that only goes 1/4 mile between rebuilds, like a top fuel dragster, will have short straight pipes out of each exhaust port.
I always say it, so, I'll say it here. Go for the full debaffle! It's not much louder but it's much much deeper and throatier!
The only issue you MAY have is running a little lean due to less backpressure (thus more air can get into the cylinder). However, the presence of the cat converter generally makes this a non-issue, as it probably causes the most restriction in the entire system. However, without a fuel process, I would NOT run any aftermarket air-intakes with your debaffled exhaust.