is it better to add 3 teeth to the back vs.dropping 1 off the front?i know price is different but only concerned with performance.

its the same for performance.
1 off the front is equal to 3-4 teeth added to back.

adding 3 to 4 teeth in the back is like dropping one in the front :shock:

I would rather add to the driven sprocket than reduce the drive sprocket, the effective gear ratio is the same but the life of the chain and the strength of the chain to drive sprocket is greater due to the greater contact between chain and sprocket.

As you know, when you reduce the diameter of the front sprocket the chain has less contact at any given time.

If you change the front you can get away with using the same chain and just adjusting it in/out. If you go the rear route you need to get into additional masters.

It also really depends on the amount of gear change you are after. Big changes need to be done with the drive sprocket and then you can "fine tune" with changes to the rear.

A few other things to consider is proper chain alignment and clearance, if you attempt to go too large or too small, your chain guides may get torn up or simply not work at all. You also want to make sure that you have some room for adjustment left after making a gear change.

Many times I see people spend the time and money to make a change and end up changing it back because they didn't think it through! If you are lowering your gear ratio, will your 1st gear still be usable? If you are going to a higher ratio, you may never need your top gear again except on a dry lake. If you are attempting to cover up a gap between lets say 2nd & 3rd, the gap will still be there but will hit at a different speed. Gearing down may get you past that gap easier. I would still prefer to re-gear the trans to get rid of it all together. The only time I put a gap in the trans ratios is between the top two gears where you won't notice it as much and it will act as an overdrive.

You will definitely want to experiment at least some with the your different sprocket/tire set-ups. Each bike is a little different, plus tire differences, and weight of the rider.

Some time back, I had an '88 250R.
Best performance with stock tires = stock gearing.
Best performance with "Hauler" paddles = stock gearing
best performance with "Sand Skate II" paddles = 1 tooth lower on the counter sprocket.

I now have a 400ex. Best performance with "Sand Skate II" paddles = down one tooth on the counter sprocket.

If you find that one gear set-up is too high, and the other is too low, I'm certain you can find a matched set that will split the difference. Either way, it is easier and cheaper to at least experiment with a smaller counter sprocket first.