If you want to run mods , get an rgh falcon, japser, or Trinity, trinities are the most reliable imho
Jtags are more reliable then rgh (exploit wise they instaboot %100 of the time), but 98% of jtaggble units still around are xenon and zephyrs, I would not pay more than 100$ total, less than $250 for a falcon or jasper as those are much more rare to get a low bootloader revision to jtag
If you just want to play pirated isos you can either reflash the DVD drive or get a drive emulator (xk3y)
Rgh is based on a hardware GLITCH (just like games glitches, they don't always work the first time, has to be done just right)
Jtag is based on a software bug (who ever compiled the 4532 bootloader fucked up the code by misusing one CPU instruction, the CPU instruction used was a 64bit instruction, but was used to compare 32bit datatypes ), but can only be accessed by modifications to allow dma via the jtag port
THE ONLY 360 SOFTMOD AVAILABLE AT THIS POINT IS USING MICROSOFT'S 360 PRIVATE SIGNING KEY......
I'd recommend the op buy a premodded unit, soldering jtag is easy, but most people will not be able to solder the rgh, imagine soldering to points the size of mechanical pencil lead for rgh