Looking for some feedback in terms of which build makes sense.
I already have the flat pack for a 100L box.
I also have the option of using a iNuke 6k or LG clone.
Would running the LMS at double the 'datasheet' RMS be a major issue?
Using a LMS will be fine utilizing 1000watts. I would recommend using an amplifier that can put out 2000watts anyways for each sub. Majority of the time your sub will never actually see 1000watts. So you will be fine using even more power. It will be good for transients and sustained bass durations. Having not enough power with allow the amp to clip.