Have Dinan Stage II and happy with it. However, as I never had ESS, I can't really compare.
I got Dinan stage II when I had full Dinan setup. Then I went back to Stage I tune after I took full Dinan off.
And I recently flashed Stage II again after installing Akra Evo.
Good thing is: My local shop called Dinan and got a confirmation of my Stage II tune ownership. So they re-installed Stage II at 1/2 hour labor only.
X5M: Dinan Exhaust | Dinan Suspension | Velos Tune | BMW Perfomance Splitter | Lux V4 | Euro Mirrors | H&R 12/25 mm Spacers | IND Cosmetic Package
PAST: 08 E90 M3 | 08 E92 335i | 03.5 E46 M3 | 99 E36 M3