I'm about to flash my Liteon today with firmware 1.51 that supports the wave 3 games. Is there any new firmware out there or anything else Microsoft is going to do (wave 4 or whatever it may be called) that I should wait and flash it later? I am paying someone that's why I ask. i don't want to pay today, and then something new comes out and have to pay again.

new firmware is due to be released on may 14th however however nobody knows what MS plans are. its unlikely to see wave 4 soon since wave 3 is new

TBH, if you can wait, I would wait for the 1.6 release. the 1.6 fw supports wave 3, SS V2, 0800 (for ripping games if you dont have a kreon drive) and also utilizes the "one-shot bootloader" (allows booting of game disks that dont normally pass the strict checks of the FW), where as 1.51 only supports wave 3, thats it.