Looking at the iFixit guide for replacing your airport here: https://www.ifixit.com/Guide/MacBoo...226+and+A1260+Airport+Extreme+Replacement/664I can open my MacBook, I've already changed the hard disk with a SSD. Do you know if your mCard 2 is compatible with a MacBook Pro early 2008 mounting an Airport Extreme bcm4321?
Your 15" MBP only has the 2 antennae connectors, so, yep, it'll be compatible. Same slot connector as the 17" MBP.
You'll also need to remove the separate bluetooth module, as the mCard2 is both bluetooth and wifi (this gives you BT 4.0LE as well as 802.11AC) - using the iFixit guide here: https://www.ifixit.com/Guide/MacBoo...226+and+A1260+Bluetooth+Board+Replacement/666
Edit: btw...had you looked on QuickerTek's site, they do list your 15" MBP in their compatibility list for the mCard2: http://www.quickertek.com/manuals/CardCompatibilityChart.pdf