A bigger IC alone isn't going to make a whole lot of difference performance wise. However, it will allow you to run more fuel.

Keep your fueling the same + add bigger IC = not much but lower EGT's
Add some fuel + add bigger IC =

I don't get the impression that the chiptuning for the OM606.962's adds a whole lot of fuel. Then again, I've yet to see any EGT data on a stock/modded OM606.962...

Like others have said before - the OEM turbo is a MAJOR restriction. I honestly wouldn't push it much past OEM fueling. It SINGS and you can tell the wastegate is almost always open. Nothing wrong with that, per se...just no good for the top end and making more power in general.

Cheers,

Matt

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'99 W210/OM606.962 - bone stock for now.
'94 Dodge/Cummins - NV5600, P7100, ~400hp
'96 Jeep ZJ - Cummins ISB 170/Allison LCT-1000 conversion project basket case
'00 VW Jedi - 345k, bone stock