I'm kind of embarrassed to ask, but I don't know the answer...

When you put a tune on the car, are all the modes affected? Does the mode selector still work? I use comfort when I'm going to be on the highway for over and hour, but S+ around town and occasionally R when I'm out with a group for a spirited afternoon. I'd like C to remain sedate, but be able to turn it up when I'm in the mood.

 

An aftermarket tune you can buy through most vendors will keep standard functions in place. They all generally use the same map save for a few minor tweaks to call it their own.

If you stick with the popular brands “box tunes” you will be safe.

 

You will have more power available in all modes but the driving characteristics of the different modes will remain. You can still cruise at 2000rpm in comfort mode.

 

Awesome. Thanks.

 

Agree with both Bill and Kumizi. Whatever the engine output is in HP/TQ is the same in C, S, S+, R. These modes are essentially TCM mods (with exhaust note options when dual exhaust modes exist).

The plugin tunes are all pretty much the same. They adjust timing (where every manufacturer I know leaves HP/TQ on the table). With any plugin, where an actual tuner can't see the numbers, timing is the only safe option. You cannot mod fueling w/o seeing the output of the change in terms of AFR, in PE. Fuel trims are fuel trims (where we spend 99.9% of the time driving on the street), but PE is dangerous if one tries to mod a PE fueling table sight unseen. On NA cars, I've seen AFR in PE around low/mid 11s, sometimes in the 10s, with a factory "aggressive" tune. This is pig rich (but manufacturer safe). A good tuner who actually sees the tune and with car on a dyno or street tune with DL (which is what I prefer), will shoot for 12.5:1. Boosted engines like this one will run best around 11.5 to 11.75...Still suicide if tried via a plugin. On a forced induction engine like this one, the difference between 11.5 AFR in PE and 13 is the difference between a safe engine and engine death.

Back to timing. Plugins usually just grab at timing table numbers and rely on knock reductions to manage timing adjustments. I don't like this but it's done. When I've tuned, I spend my time DLing AFR in PE with a wideband to get that perfect; then DLing short WOT runs spending lots of time finding the knock bursts and adjusting individual timing cells to get a perfect outcome w/o the ECU constantly bouncing off knock spikes.

I'm starting to get my arms around this ECU. It uses 4 complete high octane timing tables. The knock protocols on this ECU are sophisticated and more thought out than most others I've seen. The timing tables and knock screens on the AMG look like this. The insert views comprise 1 of the 4 main spark tables which are seen in the upper lefthand corner of the main view. Shown is the Intake max exhaust min timing table with one associated spark offset and one spark knock offset. The plugins only mod the first screen, then let the knock tables do all the work (which again, I don't like as good tuning practice):

 

And THAT is exactly why I have to pay someone for a tune!