Tinkering is a very niche card that has had some use out of decks using Rielle "Kit" Peddler: Transhuman or maybe Quetzal: Free Spirit(Though the influence would be very tight then) to get more out of their base abilities. Paintbrush Kit it hasn’t really seen a lot of use, which maybe should be thought about in a different light.
The big thing that is often overlooked on Tinkering is that it does not have to be on a rezzed piece of ICE. Any ICE can be targeted with Tinkering, even unrezzed pieces, giving the runner quite an opportunity. It becomes a Shaper version of Inside Job, when the runner only has a single breaker out. Certainly no where near as effective, and without knowing what the ICE is trying to calculate the cost of the run is very difficult, but there are ways around those issues.
Though it has not seen a lot of play, it is certainly a card worth re-looking at and considering again in a different light. If seen early enough it can help get into servers the corp thought were safe, and even late game it can allow more efficient breakers to work on ICE that is costly to get through for another type.
(Written during the meta of Breaker Bay, part of the SanSan Cycle. For more reviews like it, visit wyldside.blogspot.com)