I got the Cobb thinking I would only go tune and liked the ease of use. The simple flash process and tunes available made me get some hardware pretty soon. What I am saying is that Cobb makes you catch the bug soo easily. If stage 1 is what you want for sure I would say GIAC even though Cobb is great and gives you updated maps every once in awhile.
I went FBO + E85 a while ago and would never go back. You get so much return on small investments in mods on the x35 machines.
E92 335i tt 2007 track edition