Question(s) about upgrading MBP HD

Question

Ok, let me start off with the system basics–
Model Name: MacBook Pro
Model Identifier: MacBookPro3,1
Processor Name: Intel Core 2 Duo
Processor Speed: 2.6 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 4 MB
Memory: 4 GB
I currently have a Hitachi internal HD, the 200GB 7200 RPM option that came as an option on theis particular model of MBP.
Intel ICH8-M AHCI:
Vendor: Intel
Product: ICH8-M AHCI
Link Speed: 1.5 Gigabit
Negotiated Link Speed: 1.5 Gigabit
Description: AHCI Version 1.10 Supported
Hitachi HTS722020K9SA00:
Capacity: 200.05 GB (200,049,647,616 bytes)
Model: Hitachi HTS722020K9SA00
Revision: DC4AC77A
Serial Number: 071212DP1410***5WP
Native Command Queuing: Yes
Queue Depth: 32
Removable Media: No
Detachable Drive: No
BSD Name: disk0
Partition Map Type: GPT (GUID Partition Table)
S.M.A.R.T. status: Verified
I am in dire need of more on-board storage. I frequently travel, and toting an external HD has become exceptionally awkward, especially through airport security and customs.
To forestall the inevitable suggestions, no, I cannot use a web-based storage service, as I'm frequently in areas without access.
Now, here's what wanted know:
1) The Link Speed of the HD is 1.5 Gigabit, so I'm assuming that means that it's an SATA 1.5 interface. Now, if I were to install an SATA 3.0 Gigabit HD in this laptop, would it just step down to match the 1.5, or are they two completely separate, non-compatible interfaces?
2) I have a stationary external HD that I use for making Time Machine backups when I can. If I install a new drive, all I should have to do from there is install OS X on it, and restore my backup from there, correct?
If I need to do a flat reinstall on everything, that can be done as well, but I'll need to notify some people that I'm grounded for a few days while I get everything back to working order.
Any and all help is greatly appreciated.
<Edited by Host>

Answer 1

1) Thanks, that alleviates my biggest source of concern. =)
2) I've done full restores with TM before, and I rather like that it's fairly stupid-proof. I'm fairly good with hardware; however, my wife calls me the Reaper when it comes to software-end things.
I'm going to mark this as helpful, because it has been very much so, but I'll leave it as an open question until I get the new drive in to do the install.
Worst case, I play a game of musical hardware and give my 6mm Torx a workout.
As far as repurposing the old drive, I have an ridiculous amount of external storage, so that's not an issue. Frankly, I'd prefer to pickle & box the old drive as an emergency backup, on the off chance that my new one fails; I don't know about you, but I can't just run down the street and buy a 2.5" drive at the drop of the hat.
Yay for all the decent stores in my area being put out of business by Best Buy.