Be aware, that some laptops will not accept different cards, I have a HP one here, which fails to get past the BIOS screen if you change the internal card. It just says the hardware is incompatible.
I had a similar issue with an ACER Travelmate 2000.
I fitted a micro USB wireless "n" adapter instead,
Yes Keith - I have read before that some laptops are more difficult to find matching cards. For my first upgrade I used the same make as the installed one - for the next one I looked up compatible cards and found the Intel 5100 (Wireless n 140mbs). My latest upgrade was based on the hope that the Intel 5xxx range should be compatible and as the price is pretty low I took a chance with the 5300 which has 3 antenna conections and offers Wireless N at up to 450mbs although I "only" manage to get 300mbs. My laptop is an approximately 4 year old Aspire 5920 and has 2 antenna fitted as standard. I pulled another out of an old broken laptop and ran the antenna around the base section approximately around the keyboard.
I shall be taking the plunge again soon with the Intel 7260 wireless ac card http://ark.intel.com/products/75439/Intel-Dual-Band-Wireless-AC-7260- it also has a built in Bluetooth 4 option but chances of the bluetooth working are very slim and I will be be very lucky for the card to work at all - but if it doesnt then I can sell it on ebay and it would not have cost much overall. Its a half mini size so I will need an adapter (they cost about £1.50)
Another consideration with pci-e wifi cards is that they tend to be made for specific models of laptop - hence the problem you had with locking up your bios. Although each upgrade has worked fine with Windows 8 native drivers its not been possible to load Intel specific apps and drivers so I may not be getting the best possible performance, however compared to my sons 6 month old I5 Asus laptop my wifi performance is much faster and in some situations more stable.
I have to say my laptop overall performance matches many new ones except on the graphics side (but I dont play games so no problem there)- mainly because I have fitted an SSD drive and that is definitely the best upgrade anyone could do - but its interesting keeping an aging laptop up to speed and of course the battery drain improves from the lower power consumption of the SSD and the 5300 card.
One other point - a problem with the mini USB adapters is the very small antenna. I have got a Wreless ac dongle and even though its quite big it cant match my internal card when running on 2.4g typically running at 144mbs compared to 300mbs. On 5gb it reaches 846mbs but quite often falls back to 2.4 (still havent figured out why) - in fact I just checked and right now it running at 117mbs so the big internal antenna is much prefered.