Congratulations on your new purchase! Welcome to the big wide world of Rigol1052E users thanks to Dave's excellent review of it way back in the early days of his video blog.
The mod to 100mhz is really simple so you might as well go ahead and do it. I'm not sure if you have seen it or not but Dave did a whole step by step video of the process on his blog. The video is still there if you haven't seen it.
Also, don't forget Dave's famous saying,"don't turn it on, take it apart!" Go ahead, don't be scared, void that warranty and enjoy looking over the guts of your new piece of test equipment.