If you have nanocom watch the IAT and MAF readings when that high EGT occurs... also if the crankcase breather(depression controll) valve is old replace it just to rule it out cos an old one can mix up MAF readings also it will be excess of hot air in te intake which leads to higher IAT and so on
if you bypased the wastegate modulator shorten the rod with 3-4 threads to increase boost a bit also unplug it's electric connector to make the management go into default with that otherwise the whole fueling is mixed up due to the fact that the addaptive strategy for acceleration expects a certain boost according to the wastegate controll ratio and it gets something different... it depends very much on the fuel map version though so only a drive test with the modulator unplugged is really relevant, it can be better or worst only the reality is important

