I run an YBP engine.

The YBP block uses oiljets mounted directly onto the block and because of this a regular pinto oilpump can be used. Or in my case I used an uprated high capacity/high pressure pump. This will fit with a little modification. Still alot cheaper than a regular cosworth oilpump.

The last t25 engines has m6 bolts on the cam bearing caps and are not suited for uprated valvesprings and/or wild cams.

It has bigger waterchannels in the head so not ideal for your 700+bhp enginebuild because the port size is limited by this. Not a real problem on a more "normal" 5-600bhp engine tho.

It also has new and stronger flushmounted valveguides to improve flow.
Bigger plenum elbow and throttlebody to.