The previous generation of ThinkPad, with models such as X240, T440 and T540, introduced a new touchpad without any physical buttons, also known as a clickpad. By reading reviews and comments, it is clear that this change was by and large met with dissatisfaction. The reason being that it was hard to use the trackpoint without the physical buttons at the top of the touchpad.
I only used the clickpad on my T440 for a few days, but long enough to understand why people were complaining. The first problem was the lack of tactile feeling of where the left, middle and right buttons where, therefore I often did a middle click when my intention was to do a left click. The second problem was that I would often move the cursor slightly when pressing down the clickpad. Thirdly, it was also quite hard to select text using the trackpoint with the software buttons.
Luckily Lenovo realized their mistake and brought back the physical buttons to the top of the touchpad in the latest iteration of the ThinkPads. Even better, the touchpad for the T450 has the very same size as the one in T440, and I believe the same is true for X250 and its predecessor X240. People soon found out that it is fully compatible, and only requires you to order a touchpad and replace your current one with it. I was compelled and wanted to do the same upgrade on my T440.
As I wrote in my previous post about my T440 purchase, it feels like disassembling your T series ThinkPad is encouraged, which certainly shows when performing this modification. Lenovo has a great hardware maintenance manual that, among other things, exactly explains how to remove the keyboard and system board, which is required to replace the touchpad. Note though that the manual might not be 100% the same as the ones for T440s and T440p.
A T450 touchpad can be purchased from Ebay or Aliexpress. I got mine from Aliexpress for about $75. I assume it will go down in price over time, so if you want one but think it is too expensive you might want to wait.
To my help performing the touchpad change I had the Lenovo manual. But I also found value in this thread, especially the first post, even though it was a little hard to read. Even better, there is a guide with pictures illustrating each step to replace the touchpad, however, it is in Chinese, but the pictures are still great.
All in all, I believe it took me about one to two hours to perform the whole process. There are quite a few screws, cables and components that need to be removed and unplugged, which did put some pressure and stress on my mind. I would only recommend doing this if you are able to stay cool. It is not hard to do it, but I became quite nervous towards the end that I might had screwed something up and that it would not turn on again.
The new ThinkPads’ touchpads do not work correctly on Linux just yet though. Work is being done and fixes have been committed to the kernel. However, it will take some time for them to trickle down to your distribution of choice. In the meantime, there is a quite easy workaround that will make the T450 touchpad buttons work on Linux, with the downside that gestures, such as two-finger scroll, will not work. I am myself running Fedora 21 and it works great with that workaround; touchpad scrolling is not super important for me, since I usually scroll with the keyboard, so I can happily wait until the patch eventually trickles down.
A last resource I want to mention is the subreddit thinkpad. It is a great source of information and news. It is also a great place to ask fellow ThinkPad geeks question about anything that might pop up.