MAF.ia's work really great - there is NO downside to them at all. All it does is the same thing that the higher capacity MAFs do electronically, except they do it externally. They are easier to tune and if you use your stock MAF, you can expect to retain stock driveabilty without the MAF pegging. Keep in mind, this is coming from someone who is an SCT dealer. We use them a lot - I have one on my Gen 1 turbo Lightning - with LMAF electronics in a 3" tube - it made 481/635 with the stock engine.