no you should be fine, you just put the cap over the thread...

Yeah its a pain getting to the airbox or battery, You have to take off the seat and the whole side panel, The air box is on the left side when sitting on the bike and the battery is on the right... When you take off the panel there is a screw under the mud flap thing It wont come out without removing that and you don't need to completely remove it, just have it move away enough to get a screw driver and wrench under... and if its your first time removing one of these panels there is a part that just pops in and out without screws so if it catches thats normal just wiggle it out....

If your going to mess with the air box there is alittle clear plastic tube sealed shut clamped on, take it off and that will drain any oil you have in the airbox, make sure to put the piece back on after. As for the peice you need to plug up anything that will seal it possibly even duct tape but that is a temp fix, I just cut the hose shorter and caped it off.

Well I decided I wanted to modify my bike alittle I don't need more hp but would like better responsiveness ect... And didn't want to spend too much, or put too much effort into it.

there are three things to look into:

- A breather filter to replace the tube that goes to the air box... This keeps you from having oil sucked up  
into your carbs at high rpms, This mod cost about $10 and all your doing is replacing a tube with a filter, Make sure you plug up the port in the air box after. The size I got for the breather was 3/8"-1/2" if they don't have one that gives a range like that its more toward's the 1/2".

-better spark plugs, this is almost an obvious one because its around $10 at the most and it gives you much better spark, I recomend the Ngk iridum.

-High perfomance air filter for about $25, no I don't mean a cone filter, It is very easy to modify your stock filter its is just a peice of foam screwed between 2 plastic peices... I had an Uni filter I was going to put into my suzuki before it brokedown (the type that you don't have to rejet for, Any brand foam filter will do just make sure it is ok for a stock replacement).

here is the step by step:
unscrew the two plastic peices and remove the old foam filter
-I cut out the two layers of foam from the uni with a steak knife
-I cut holes into the center of each layer
-I lined up the holes with the plasic holders and screwed it all back together
-Then just cut off the excess.

It is very important that if you use a uni you make sure the denser foam is facing the carb and the lighter foam is facing the air hole.

With these three mods I spent less than $50 and got far better throttle response, more power at lower rpms, and No random bogging at high speeds.

from what I hear this is one of the main issues with the design, I myself am going to head out to an auto parts store and pick up a breather filter and just remove the tube and give it its own stand alone setup... and you shouldn't have the problems in the future...

well the guy I bought mine from has over 6000miles, and still runs like its new, he let me compair his to mine, but he said the big thing is to not push the bikes... 70mph on these is like doing 100+ on a ninja, the higher the rpms the more wear on the motor, here if you stay off the highway our roads have a speed limit of 45mph, so i figure I can still speed alittle and not hurt the bike but if you want to go faster, I seen threads on different forums about changing out the sprocket one guy put a 36 tooth rear on and said he got up to 75mph in fith gear at around the 5-6 mark on the tac.

I personaly just got my 250gs today and After giving it a good ride, I can say I wouldn't drive it more than 60mph in its current state without killing your motor, But If you were to change out the sprockets you could get a much higher speed at lower rpms, I would recomend getting a replacement rear sprocket with around 36-38 teeth, since its smaller it will turn faster, you loose alittle on take of, but lets face it, These bikes arn't exactly ment to tear it up off the line.

If you did change the airbox, you would need to either hook this system into the new filter, or cap it off.

You could always extend the tube and have it work as a overflow