Hi E92 Fan,
I've got a 135i and have had it fairly extensively modded through Birds using the same thinking as you ie handling first, then power. So I've got a Quaife diff, Hartge adjustable suspension, Hartge anti-roll bars etc.
I'm now thinking about increasing power and I suppose my options are the Dinan kit that Birds can supply, the new BMW engine tuning kit shortly to be released, or the DMS reflash.
I think we can discount the BMW stuff as it only adds about 20bhp and no doubt will be very expensive, although it does include additional cooling.
I presume the DMS remap and the Dinan remap will be similar. I do know that Dinan are more expensive but they offer a full BMW-matching warranty. However, I don't feel that confident of having a supplier based in the US if I encounter any problems.
I suppose that leaves DMS. Now that you've had it for a while I wonder if you could let me have the benefit of your advice/guidance. Do you feel the fact that the BMW kit includes additional cooling means that any tuned car should be looking at this issue for reliability? Were you at all concerned about your warranty (I still have 2.5 years to run).
Any advice gratefully received.