IMO they are not worth it...
I had one on my car and it sucked up water and hydrolocked...
It may add a couple of HP, but if you happen to drive in areas where it rains hard, or there are large puddles, you are gonna need major engine work...
My cylinder 1 connecting rod bent like a banana due to hydrolock...
Only option is to buy a PATENTED AEM bypass valve, not the cheap ones on ebay...
I say save your money for a turbo