Uggh, I don't mean to inflame, but I just feel I need to speak frankly.
There is a deeply held belief of the culture of this forum that rain ingestion is a real damaging entity. I would ask for substantiation of this theoretic concern, as I will contend that it is simply a myth.
I would advise that the aviation community has been using our Subaru engines, with raw ingestion of foul weather for decades. Their intake is basically some foam and about 8 to 12" of wide ducting... pretty much like a 'gravelsport'. What is more is that the typical cruising revs of these aviation engines is about 2400 RPM, not atypical from ours. The interest in the EJ blocks with essential stock internals, has only grown in interest as a very robust and reliable engine in the interim. As you can imagine, this is with very strict concern of resultant damage from adverse weather conditions. The fact remains, ingestion of rain into these engine poses no adverse effect as determined by people who places the lives of themselves and their passengers on their engine's performance ... and of the liable bureaucrats that insure this practice. I would defy (and, in fact, appreciate) anyone to find evidence to the contrary.
Now, hydrolocking is a large and sudden bolus of ingested non-compressible fluid, such as from a cold air intake introduced into standing water. No question this is a cause of real damage. This is an entirely different entity from that of raw rain ingestion.
There are many who have plugged a cone on the intake and noticed loss in low end ... something about a standing wave to maintain this...but the physics is beyond me. The intakes that perform have a minimum length.