Better to tune from Base tables or GMPP Tune? Redline/GXP/LNF

[npaz]

There is general agreement on a few forums that the GMPP tune updates several tables that are not accessible via HPtuners and thus don't get rewritten once installed. I've read that these hidden tables hurt later non GM tunes, as the base tables are better for HPT tunes.

I tend to believe at least the extra tables part of this because the GMPP file size is almost twice as big as other tune files. On the other hand, any tables built based on higher hp and torque would seem like a better starting point for further upgrades than the base tables.

Anyone have some experience with this?

[cobaltssoverbooster]

most people start with the original OS and just transfer all accessible tables over to that OS from GMP file in the repository. I find this method easier and i don't end up paying the dealer extra money for an OS Upgrade that is now far out of warranty. It is possible to tune the accessible tables to get around the issues people were having in the past if you decided to switch the OS via dealer flash. The first way is just more effective and cost productive.