LISY does not only replace the original MPU by 100%, it also provides you additional Features such as a web based test (LISY_control), optional Soundboard, Freeplay Option and no need to use batteries any more. For a full list of Features have a look into the user guide
No, you need to solder yourself or find someone who can do it for you. However soldering a LISY PCB is not difficult, just give it a try. Even for unexperienced People it can be done in less than three hours.
Just send me an E-Mail (contact) or have a look at german flipperforum Flippermarkt there is a big community with experience with LISY boards where you place a question and/or contact me there (nickname: bontango)