I "had" one of those pumps. You can open that up to at least double the current size but there is a turn in the port and you'll have a problem going much past it.

For what 440Source paid for those I think they should have scrapped the lot and saved themselves all the bad press.

Whether or not there were any "real life" issues due to the pump themselves is hard to say. You have to figure that someone putting on one of these pumps has done other mods too - which could cause overheating issues.