I'm about to embark on the 411 swap, but will require some help from HPTuners along the way. Reason #1: it appears EFILive doesn't support the series II Gm 3800 engine found in 97-03 Pontiac Grand Prix and various other platforms. These are the injectors I intend to run with my marine intake swap so I'll need flow data and injector latency values I imagine. I'm fairly certain that HPT supports this engine and would be able to provide these values, but I don't know if they'd be in the same format so may require flashing with HPT? Another huge reason is my TCC unlocks when I lift off the throttle and apparently HPT was kind enough to unlock the cell that allows you to change that, but only with the 411 swap.
So I'm wondering, do I leave the Express van tune on there, change what I want changed in there, then swap to COS5? Or will the OS change wipe everything out? If so, will HPT even be able to do any of these things once COS5 is flashed on?