The PTIT measuring on the 1T engines has been accurately fudged so that whilst the guage indicated limit is still the same (795 degC PTIT) the actual PTIT is higher allowing more power to be pulled. The only difference I believe is that whilst the Max con on a normal engine is not cumulative, on the 1T it is and after amassing 2.5 mins the engine is rejected.
The combination of the two mods gives a large increase in hot and high performance which is exactly as claimed by Mr Carson - the Sea King fleet could be given a 'late-life' update that would give immediate performance benefits and probably save a lot of money in the mid to long term - so it probably won't happen. If they carried out these mods and an avionics upgrade on the Mk 3s we wouldn't need shiny S92s or 139s to do UK SAR
Two problems with the above.
-1T engines do nothing at all for you until the temperature gets above about +30. So for most of the time in the UK they are not worth having (bloody marvellous in the sandpits though).
Whatever you do to a Sea King, and I agree Crab's analysis that with Carson blades and modern avionics the machine would be transformed, in the last analysis its still a Sea King and needs something like 30 maintenance manhours per flying hour. Modern helicopters are an order of magnitude better than that. New aircraft are at least highly desirable, probably essential.
Sven