Here is a link that we have been using for a long time to determine what the lowest rolling resistance tires are. Thanks to Al Morrison for doing all the hard work, maybe he will come out with a new list soon? I would love to see some wider 25c tires tested, and maybe a section for lower end training tires. Also a column for the weight of the tire, including rim strip and tube for clinchers and the weight of the glue for tubulars.
This list is definitely something that any weight weenie worth his salt will look at. At this level of precision you need to start balancing the weight of the tire vs the amount of rolling resistance.
Here we have a set of THM M5 Cranks with an SRM on them. The total weight was only 698g, which is only about 110g more than the cranks would weigh with out the SRM. These are a bit heavier than average also because they are 175mm cranks and they use a BBright, which are heaver than the standard english bb cups that the cranks come with. The reduced weight does not come cheap though, the cranks retail for $850 and the SRM power meter, which has to be shipped to the US from Germany, goes for $2695. The total will be around $3600 with the bottom bracket, but hey, how good does that crank look?
The spider is also a bit funky on the SRM with a 110bcd outer ring and a 130bcd inner, which limits your chain ring options a bit.
698g Power Meter
Back of the SRM