How does one change the the DPI and is there any negatives from doing it?
Simply download DPI changer from the market.
There usually aren't any in all of my other Android devices, but it doesn't work too well with the TP. The homescreen gets weird. Icons can be placed off the screen so you can't touch them. I need to test a lot of different DPI to see whats best though.
A big downside is that the market will sometimes say your device is not compatible with an item if you have a non-standard DPI (120, 160, 240). There's a hacked market that works sometimes, an app in the market that will permanently fix it for 3$ or so, or you can change the DPI back to normal anytime you want to check to make sure you have all of your updates.
Having more space on the screen is a huge benefit though. Even compared to the CM7 3.5 I feel like there is so much less fitting on the screen.
Also, tried watching a 1080p video captured from my Galaxy S2, and it lags on the touchpad and also sound cuts out. I have better video quality when streaming it using Splashtop from my desktop lol.