I'm well outside of warranty and plan on doing all the maintenance myself anyway.

My interest was purely in minimizing downtime vs sending the DDE out to somebody.

So a second DDE could help here as well.

Unfortunately, the only way to disable the EGR/DPF/SCR is with a tune. Heck its really only been the last 2-3 years you could even do this. Plus when you disable the DPF you will have to remove it and install a downpipe and remove the SCR as it will clog up with soot fairly quickly without a DPF to filter the soot out. So some downtime will be unavoidable for more than just tuning.

They say modding is a disease, and you should get friendly with the rental car counter, the tuning company and an indy when doing all of this. I'd also recommend a good code scanner.

I've got INPA on my laptop for me e46 and e38. I need to update it to work with the e70.

This is my wife's car, I'm only interested in the delete for reduction of complexity and increased reliability. Any power gained is just a side bonus she won't need.

I plan to do the hardware myself.

I've kept my e46 going for 6 years and 75k miles without ever seeing a shop other than my own.

Yup, there are a lot of sensors and other issues with the emissions on these cars. Personally my biggest concern was CBU after reading the horror stories of others and having to have my car cleaned at 28K miles (originally a California car I bought used)... So as soon as the warranty was up I removed my EGR and installed the EGR race kit (my cooler had cracked another common issue). To my happiness I checked the intake and found nearly 0 CBU on the car now at 54K miles (running EGR blocked since 51K). I suspect the better diesel here in Texas helps. (nationally Diesel is a minimum of 40cetane, and in most of Texas its 48cetane min). Higher Cetane helps ensure complete combustion, less soot, which ends up recirculated into the intake.

My Diesel has been highly unreliable, so I've taken the approach of tuning out the emissions components as they fail. DPFs seem to last a long time on these cars and aren't a major concern. DEF tanks fail frequently but there is no a cheap repair available for them.

I've reviewed the very extensive service history on my 2009 @ 120k miles and there's not a single mention of any emissions related failures. I don't know if I should be impressed, or counting the seconds until a failure occurs.

FYI - Tuning Tech Frank Smith, does a diesel tune for our 35d

He's out in Crofton, MD

I have his tune on my E39 M5. Love it!

I wouldn't be surprised if you've had sensor failures in the emissions chain. But you would be a vary, like the only one I've heard of not have their SCR tank fail or NOx sensor. The EGR is not likely original on your car as there have been BMW campaigns to replace them. Consider yourself lucky :-)

My 2011 335D (very similar to the X5 35d engine), has had 4x EGR coolers, 3x EGR valves, 1 DPF, 1 SCR, 1 DEF Tank, 4x NOx sensors, 4xMAF sensors, 4xExhaust pressure sensors, CBU cleaning at 28K miles, Vacuum hoses, Exhaust pressure sensor hoses, all under warranty. Then when my EGR cooler cracked for a 5th time (loss of retainin bolt that was under recall), I opted to tune the car. BTW it just hit me with an SES light again, for a bad intake temperature pressure sensor. Most of my failures were bmw throwing parts at the car to try and get the SES light off. BMW's master mechanic flow in to Houston did figure it out before the warranty was up with a 3 month stay in the dealership and a PUMA case.

Mine is not the worst, many who had early CBU cleanings had to have all their injectors replaced and sometimes their DDE.

But BMW has really improved their systems.

I'll be taking my intake off this weekend to replace the glowplug module, which failed because the thermostat has failed open. I'll be curious to see the state of the intake.

I really want to do the PCV catch can mod to help with that, but doing the EGR delete will go a long way.

So given that I am looking to keep all Stock Emissions Components in place, but want to 'uncork' a bit more of the engines potential..

Are 'Piggy Back' Tuning solutions okay at this level, or are they still a serious compromise over flashing the engine computer? And if so why?

I'm really not looking at making a big investment in tuning, and turning out monster power. And I'm definitely not willing to end up with a luxury car that belches smoke under hard acceleration, no matter how much power it puts out..

I'd be okay with eliminating the EGR, and coding out associate parameters, but I'm not looking to remove the particulate filter, etc, etc at this stage of the game. If they go bad and aren't covered by Warranty in the next couple of years, my attitude may change, but right now I want it to stay a clean diesel..

I would talk to DUDMD Tuning. They have a stage 1 that keeps everything. Or Dmitriy should be able to just code out what you want.