I recently made a few modifications to my Dell 9300. I ordered 3 parts from ebay and one from laptops4me.com. I got a 7800 gtx go

, 130 watt ac adapter, and a 9-cell battery from ebay and a processor pentium m 735 from laptops4me. I then went to a thread on the notebookforums.com for instructions on how to install the video card and processor. So it all depends on what you want to change in your computer. There were a lot of screws holding my laptop together (I think I took off 25 before I was able to do anything inside my laptop

) but if you have desktop building experience it should be cake

. You can also search for any computer related piece of hardware at pricewatch.com, and you'll usually get some results for what you're looking for.