hey checkbuzz,
i recently thought about keeping the exhaust temps down in the same area on my car.
I'm sure that if you check your EGT's they will be through the roof however obvious that may seem. From experience, this usually indicates that the tune that is not quite right however you seem confident in your tuner.
You could start by checking the amount of air flow in that region, it could be restricted by the type of front bar you have, position of your intercooler or if you have a sheilded air cleaner element (pod filter). i've seen people with large "cold air intakes" that resemble an air dam which can cause hot spots. see attached.
If you can't resolve the generation of heat then you might consider adding some ventilation to that area. On my spec m bar there are 4 inlets at the bottom of the bar. the 2 smaller ones i have already used as brake ducting to keep my brakes cool. bought some flex hose from my local rubber suplier and routed it cost me about $60 per side. the other two larger openings i plan on buying and making something similar for an oil cooler and turbo side.
Another option is getting the new turbine housing hpc coated. I had heard from a reliable source, (Dr Drift) that they make a coating that will reduce the turbine housing so significantly that after a short period you can almost touch it. cost apparently is around $150.
HPC -> http://www.hpcoating...-turbocoat.html
as for a new housing, a company in vic called MTQ, speak to gary, and he will tell you what will fit.
Ultimately, i'd want to know why the temps are so high in the first place.