I got hit by system mods as well, which is a shame since they were great when I initially ordered my X2.3 lite chip years ago. If you haven't yet done so contest the charges with your credit card company. I got the charge from SM fully reversed. Point them to Xecuter's post regarding their suspension if you need to -
http://www.teamxecuter.com/index.php?name=News&file=article&sid=203
If you haven't yet ordered, themodchip.com took care of me after the SM fiasco. Currently they've got some specials going on, X2.6CE for $45, free shipping and free X2 programmer. The programmer is an older version but works with the X2.6CE chips just fine. If you've got any friends that have modded Xboxes (or if you will soon be modding Xboxes for them once they get a look at yours...) this may be a good item to have.
Otherwise, use any reseller that is currently listed in the "recommended resellers" list on the front page.
-Whoopin'
