i dont feel like typing lol, but steel sprockets last longer than aluminum, you will notice a huge difference with -1, +2… i doubt you will ever FLIP an f3 with such a minor change (slipping the clutch will probably allow 2nd gear to come up a lot easier) but WOT i bet it will still barely lift in first unless you chop the throttle…
you can find a sprocket kit online with chain for around 150ish… ebay is full of them… as for aluminum though, second thought, your bike might make around 90 whp, i wouldnt worry to much about eating the teeth on the sprocket in less than 15-20k miles (and realistically how long do you plan on owning the bike for)
just playing devils advocate… good luck… pm me your number if you have any questions, i’ve re-geared every bike i’ve owned lol or bought them with different gearing (which i kinda regret on the 10r) but oh well…4th gear power wheelies are fun too