Bottom bracket change BB30
 

I have a 2011 Cannondale 8 with Shimano 105 components and a BB30 bottom bracket with a FSA Gossamer 39' 53' Crankset. I would like to lighten my bike and get a new crankset that speeds up my ride. I looked into the FSA SLK Pro Carbon but it doesn't
have BB30 bottom bracket.
According to a colleague of mine, I can't change the bottom bracket for this to fit onto my bike because I have a BB30 bottom bracket shell and BB30 is built into my frame used internal. and the bottom bracket that comes with the new crankset is meant for a standard english threaded which uses external bearings.

What can I do regarding this matter and how would I be able to get a better crankset to fit onto my bike. What can you recommend?

BB30 is a fine bottom bracket standard. There are numerous cranks available in BB30 that are just as light, stiff and smooth shifting as any other standard. Just search e-bay for BB30, and you'll see plenty available. As to whether they'll speed up your ride, well that's a different story- I doubt that any other crank with the same chainring tooth count would speed your ride up appreciably, but you may save a few ounces and get slightly better shifting with a better crank.

You can get threaded inserts pressed into a BB30 frame that will convert it to a standard 68 mm English shell. You can also get adapter rings that will slip over an external-bearing type crank that will allow it to be used in a BB30 bottom bracket. Neither adapter will save weight or stiffness.

FSA does not make the SL-K pro anymore they have SL-K light which is almost the same except price I think and comes in BB30. But I'm not a big fan of FSA anyways bad customer service and what ever alloy they make their pedal threads out of, suck! Sram Force cranks never failed me. I know it might seem weird with shimano but hey if your looking for carbon cranks with BB30 they have em'.

Speed is the Work you put into the riding effort, hate to break the news.
but parts matter less than training.

+1 A new crank is not going to make you (significantly) faster especially since you're already in the higher end of cranks. Maybe if you were going from some old steel POS crank to BB30...

I've never heard anything good about FSA, so if you want to replace your crank it's up to you.