OS X Internal/external drive speed questions

Ok, so because of the Christmas Sale, I finally bought the Valve Complete Pack, but my internal HD doesn't have the place to store it all. I have an external 1 TB HDD, but I'm not sure if I should use it for gaming as I'm worried about performance issues.

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My HD info, from System Information:


Intel 6 Series Chipset:

Vendor: Intel
Product: 6 Series Chipset
Link Speed: 6 Gigabit
Negotiated Link Speed: 3 Gigabit
Description: AHCI Version 1.30 Supported

ST9320325ASG:

Capacity: 320.07 GB (3,20,07,29,33,376 bytes)
Model: ST9320325ASG
Revision: 0009APM1
Serial Number: 5VD6G14T
Native Command Queuing: Yes
Queue Depth: 32
Removable Media: No
Detachable Drive: No
BSD Name: disk0
Rotational Rate: 5400
Medium Type: Rotational
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Verified
Volumes:
disk0s1:
Capacity: 209.7 MB (20,97,15,200 bytes)
BSD Name: disk0s1
Content: EFI
Mac OSX:
Capacity: 249 GB (2,49,00,00,01,536 bytes)
Available: 44.2 GB (44,19,87,64,544 bytes)
Writable: Yes
File System: Journaled HFS+
BSD Name: disk0s2
Mount Point: /
Content: Apple_HFS
Recovery HD:
Capacity: 650 MB (65,00,06,528 bytes)
BSD Name: disk0s3
Content: Apple_Boot
BOOTCAMP?:
Capacity: 70.21 GB (70,21,26,48,960 bytes)
Available: 21.88 GB (21,87,83,86,688 bytes)
Writable: Yes
File System: UFSD_NTFS_COMPR
BSD Name: disk0s4
Mount Point: /Volumes/BOOTCAMP
Content: Microsoft Basic Data

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So:
a) If Firewire 800 faster than/slower than/as fast as my internal HDD?
b) Is Firewire 800 fast enough for me to store the games on the external HDD and play? -- (I can also buy a Thunderbolt cable, but it's really expensive)
c) If I store them on the HDD and use Symbolic Links for the SteamApps folder, will the transfer rate affect playing? (as opposed to installing Steam on the HDD and playing from it)
Thanks a lot in advance!