I don't mean to sound dumb. But in limewire the file sizes are like 4,277. But in bearshare theres a lot of numbers. Is there some way to know the real size? So I can avoid fakes.

A lot of numbers?

It displays search results in bytes. 4,321,123 is just over 4 megabytes, for example.
Some programs use kilobytes (4,321 KB). Maybe that's what we're talking about.

And no, that's not configurable.

So if you you dont pay attention to the last three numbers its like LimeWire. I thought it was like that but I wanted to make sure.

The precision of the actual byte size is absolutely essential when sorting the wheat from the chaff.

Do sizes like:
872,159
15,872
81,964
223,472
783,843
71,070
123,897
178,861
202,477
535,842
and
643,767
ring any bells? ;]

If LimeWire has the option to display actual byte sizes rather than kilobyte
approximations, I suggest you use it all the time so none of those little monsters
ever gets you again.

Actual sizes also make it easy to focus searches on one particular file when
spammers are throwing so many bogus results that your searches stop before
finding what you are actually looking for. If LimeWire can't let you do that,
it's a fatal flaw.