I didn't mean to degrade the impact of the custom tcu work but the big cut I just wanted to point out was a setting in the dme, not the tcu. There's actually quite a bit in the dme related to how the car shifts and reacts, there's torque request tables based on throttle angle (which are also defined and heavily adjustable), load request AND boost limit multipliers by gear, rpm and airflow, load to torque tables based on rpm and load which effect line pressure based on the tcu calibration, and many other tables you'll find in the WIP folder in the public dme xdf related to maximum torque at clutch in the 6at and dct for various conditions.
I've toyed with the 6at xdf and done a few customs but I've just not found much utility, maybe because I don't own a 6at. I'm curious, what things do you not like about the 6at? Namely in stock form, alpina (if you've tried it), and xHP?
What I've found is factory non-sport 6at cal drives decent but has many limiters and doesn't allow full line pressures. Sport at cars were similar but a more aggressive shift mapping. Alpina raises torque limits a bit which helps run higher line pressure, but is overly aggressive in normal driving modes at moving into the next gear- although tuning on the dme torque tables can help this. XHP in my experience has fine shift points in different scenarios and removes all the known torque limiters. Again I don't own one so just curious what things you have found significantly improved from the xhp stage 3? Lastly, did you ever run a custom tune with xhp or just the ots tunes and rfp? Wondering if I should look into it more based on what you're expressing on the improvements so just wondering if you can describe them better than the timing drops (which aren't an issue on any custom tune with xhp or alpina for the most part).
Also, great time! And if he's changing up the tcu he's likely going to need to discuss the dme side with other tuners or use some sort if checkbox... but on the dme side there's a lot of hysteresis between tables in what is essentially considered a neutral network (multiple 2d and 3d tables contributing to outputs).