Thanks for the insight adrian, much appreciate it.

I've decided i'm going to get a set of these cheap OBX throttles and open them up abit/have custom throttle plates made in reach of a 50mm throttle plate, we'll see how thick the casting is on the actual throttles before I make any further statements haha

Apparently, now yes this is the internet - the new OBX throttles are 45mm at the plates, so they must be using the AE111 throttles? Which are 48->45mm from memory

Whats your experiance with 45mm throttles on a B series? More in particular 2.0L. Without pulling out the mathematical models and all that and ignoring, further from the port the larger throttle diameter is needed, etc. Lets say the old toda style throttles on a 2.0L, choke the system by far?