The reason people say it will run you lean is because it will..cooler air is more condensed air(more air molecules) and with everyone tuning(i use this loosely considerent changing jets is tuning) for warm weather since its florida...that 100shot can turn into a 125shot with a decent temp change. since it a dry kit, just swap the jet out for something smaller to be safe.

A wet kit would be no different...you'd still be changing jets.

as far as nitrous pressure..that plays a large roll in how much power you actually have (ever wonder why people buy heaters? they actually do something) 600psi on a 100shot jet would be alot less power than it would be at its 1000psi rating...also, going over makes more power aswell..some people have blown because of this fact aswell...there is a noticeable difference in a 900psi hit and a 1300psi hit.