I am a 115kg any suggestions for suspension

[dirtydog28]

Looking at a 2000 to 2002 250cc 2 stroke, apparently factory bikes are only designed for 75kg riders, do I realy need bother to upgrade the suspension for just riding in the woods and doing small jumps? I do have a budget, But figure it will cost round about $600 to mod, I am quite new to dirt bikes havent riden them for a while, any suggestions would be appreciated.

thanks.