if i leave limewire on so as to share, will this slow my my other computer use

It depends upon your connection type. For a dial-up modem connection where upld & dwnld bandwidth is combined, it will affect how much u have left over. For most other types of connections, upld & dwnld capacities are separate. Thus it should not affect your overall use whilst using the net (depending how much upld bandwidth u have.) As for affecting your overall comp., LW is like any other app & will use a certain amount of cpu & ram but it shouldn't affect anything else u do with other apps.

Or if you have a ton of downloads going with a really bad computer (like my imac) it might cause some lag if your doing other stuff with limewire in the backround.

In terms of games if you have cable/dsl you will have some %loss and might see other players warp around just alittle every once and awhile nothing too bad though.

Mac is a different kettle of fish. For windows the drag that LW has on the system is not so great. However for mac it can be considerable for both cpu & ram.