For reference PD150 has the engine code ARL.
Personally i find the EGR / ASV delete overrated, the thing is a lot of people end up ditching it after discovering it severely clogged up and in-operational anyhow so of course once its gone you're bound to notice a huge improvement as the engine can breath again.
Speaking from experience of removing it on my previous PD130 (ASZ) mk4 Golf wagon and my current PD150 (ARL) Seat Leon FR I've just opted to refit it...
The reason been for the type of driving i do which involves a short commute to work early in the morning when its at its coldest i really do benefit from the marginally faster warm up time.
Plus there's the fact you retain ASV (anti-shudder valve) which was put in place to aid shut down, whether it be a smoother shut down in daily use or in the unfortunate event of the engine deciding to ingest it's own oil.
As long as it's sparkly clean and the vacuum solenoids are working correctly i don't see any gains from binning it.