Personally, I have a DUDMD tune. I know of people that run the stage 2 without deletes- at the minimum, you should ask the tuner to turn off the egr until you delete it. I'd ask the tuner what the cost would be, such as just paying for the upgrade/ flash fee from the original tune, and then go from there.

Honestly I think this is a question for the tuner of your choice. I've put about 35k miles on my X5 since the delete in May '19, and it's been great. I know it's not the absolute cleanest tune, but it was half the price. It puffs a really small bit at idle, and hazes just like they all do at absolutely full throttle, but there is 0 noticeable smoke coming out of the tailpipe while driving normally. Dmitry is very open to discussing your best options, so I'd suggest giving him a call or a facebook message!

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'10 X5 35d- 279k mi, deleted and DUDMD stage 2, daily and tow vehicle
'01 330i- Drift car: SLR Super angle, BC coils- keep it simple
'07 335i 6mt - Sold @ 171k miles- stage 2 daily commuter for 2 years