EGT=exhaust gas temperature
if the exhaust housing is too small it gets to be restrictive causing it to get very very hot
this has a detrimental effect on he engine and should be avoided as its unsafe and will melt an engine
for a t2 to flow 200bhp its well outside its safe limit hence my comment
but a t3 will be a bit happier at 200bhp(some will still be too small)
thats basicaly what Karlos was getting at too i think