If you own a TiVo you've never upgraded but are considering it, and you've seen my writeup of my own upgrade process, and my review of a prepared drive installation, you are probably wondering what would work best for you. Before you can answer that question, a summary may help.
The DIY approach: You can go your own way
For my recently purchased Series 2 tivo (purchased for $199 - price still good until Thursday), I bought a bare 120Gb drive from newegg.com for $98, and an upgrade bracket and kit for $58. It took approximately 3 hours to complete the work, start to finish, including a couple hours wasted on research and trial and error, with about one hour of actual dismantling and rebuilding. The final product was a 188 hour TiVo at an upgrade cost of $156.
While the DIY upgrade may appear not for the faint of heart, if you've ever built your own PC you can definitely tackle this project. If you've worked with hard drive upgrades in PCs before and understand what master and slave jumpers are and what they do, you can totally do this.
The instructions that are out there are very detailed and easy to follow, and you can skip most of the tedious backup and restore steps. In reality, once I had my tivo opened up and the drive removed, I only had to connect up the two drives to my PC and run a single linux command from a bootable CD. The script was finished in a matter of seconds and the drives were prepared and ready to go.
I spent probably 15 minutes taking the TiVo apart initially, and putting the Twinbreeze kit in took another 30-45 minutes or so of reading detailed directions and piecing things together.
Middle ground: Someone does the icky PC stuff for you, you install
Your other option is to buy an upgrade drive ready to drop into your TiVo, and your task is simply to open it up, follow the supplied directions, and add the second drive. There is no shortage of small companies, websites, and professional hobbyists that offer this sort of package, including Weaknees, Hinsdale (the guy that wrote the upgrade how-to), TVrevo, 9th tee, among many others.
But what are you really paying for?
When you buy a prepared upgrade drive for your TiVo, you are essentially paying about double the price of a bare drive you could buy online. The dark secret of all these upgrade kits is basically that someone is sitting in an apartment running a program called BlessTiVo(scroll down to part 10, then configuration #1 to see the how-to on it). It's another single, one-line command from a bootable linux disk that takes seconds to complete. Then they tack on a $100 premium to the drive they bought for less than $100 and ship it off to you.
On the bright side, you're also paying for your valuable saved time. With most of these kits, all the steps that feel dangerous and cause nail-biting are handled by someone else. When your drive arrives, you pop open your tivo and put the new drive in, and you're done. In my DIY upgrade, I probably could have completed the drive install job in about a half hour.
I would even go so far as to say the Weaknees kit looks like the best deal of the lot, since they throw in their Twinbreeze kit. Where I paid $156 for my own drive and kit, they offer the same parts for $208 with the drive. If two hours of your time and some slight risk are worth more than $52 to you, the prepared drive and kit is a pretty good deal.
Do it for me: the clean hands approach
Most all the sites offering prepared upgrade drives also offer an upgrade service for those phobic to tivo tinkering. It's usually another $50 on top of other charges, and again, you're really paying someone to run a single command in linux and screw some drives in. I could imagine these guys getting the whole process down to maybe ten minutes with some practice. The main downside is that you have to give up TiVo for several days-to-a-week when you ship it off. The upside is aside from disconnecting your tivo and putting it into the mail, there's not much you have to do.
Adding in my $199 cost of the TiVo, the bottom line is that my DIY upgrade cost me $355 and 3 hours of my time. If I went with an upgrade kit, the total cost would have been in the neighborhood of $400 and cost me about 30-60 minutes of time. If I would have paid someone else to do it all for me, it would cost about $425-450 and no TiVo for a week, which you can't really put a price on :). Before I set out to upgrade my TiVo, I would have guessed the price differences would be more pronounced, but keep in mind I bought an expensive kit that most TiVos do not require, so it could have been $50 less.
When weighing the options to determine what path you should take, the most important consideration is the cost of your time. If you're busy, pay someone else to do the time consuming bits for you. The second most important consideration is assessing your own level of technical expertise. If you've tinkered with PCs before, it shouldn't be any problem, but if you're new to digital gadgets you are probably better off paying someone to do it, and as you can see, it's not that much more expensive for a total upgrade service.