The stock shifters work well and even work well with a aftermarket TCU and you can use it like you would a ratchet shifter for just manual shifting. These shifters along with the 3G shifter have brake interlock cables because they are OEM. The purpose of this is to make you press the brake in order to shift the car from park as a safety feature. You can eliminate this. The shifters are designed to have to press the button all the way down in order to shift from park so it cannot be accidentally taken out of park. It just connects the brake pedal to the shifter so you can only shift out of park with the brake pressed.
This is a mod typically done in 2Gs. The 3G Eclipse Tiptronic shifter is bolt in for 2G DSMs and with the user of a aftermarket TCU you can make them fully functioning with the transmission. You need a tiptronic shifter and shifter cable from a 2000-2005 Mitsubishi Eclipse. There are pictures and a video in the main article.
Main article: 3G Eclipse Tiptronic Shifter
Main article: Ratchet Shifter
You can run an aftermarket ratchet shifter on these transmissions. There are two ways of doing it. One is via Kiggly Blue Wire Mod and the other is using a aftermarket TCU. If you are looking at shifters and unsure of what you need to get then here is some direction. Universal 3 speed shifters can be used or more commonly shifters for TH400/ GM Turbo 400 transmissions will work. Some companies that make good shifters are B&M, Precision Performance Products, M&M Transmission, Kilduff Machine, and TCI.