-1 front vs +3 rear are very close to the same overall gear ratio.
I have put a -1 and a +3 rear, individually and combined on 4 sportbikes. Including a gen2 Busa and B-King. Personally, yeah, I can tell if the -1 front is on there vs the +3, and I prefer the +3.
All I can figure is that it is the small difference in wheelbase, as the +3 shortens it and the -1 lengthens it.
It also isn't really noticeable until I ride wheelies, which is every ride. That's where I can feel a small difference.
It's no big deal either. And, as said, the +3 is better just because you're not making the front smaller in diameter, and making a tighter bend for the chain, but -1 doesn't cause problems either.
A friend of mine was -3 front on his 06 gsxr1k.
Bike never had an issue, and felt like a tractor, but was a wheelie toy anyway.
-1 And +3 combined feel stupid quick too, and are alot of fun, they just make for really twitchy wheelies and throttle response.
A -1 front And a +3 rear combined or seperate will also fit the stock length chain, so playing around with them is cheap and easy.
Individual or combined, they aren't going to cause problems. It just comes down to how You want Your bike to feel.
The -1 or +3 individually only raise the rpms around 600 too, so rideability is much the same, just with a little more lower rpm umph.
Either or both sprockets work great with an ecu flash too. More timing at lower rpm combined with lower gearing really makes the Busa more agressive, aka more fun.