Theres no problem in building a ls/vtec, it was our first backyard ls/vtec build dup, so we did everything from our knowledge, the power it made was good for it being all stock jdm type r internals, he just ran into problems like replacing headgasket, motor smoking alot, it wasnt stable but i know of people who has done ls/vtec and still rocking it still with no problems, running correct....but then....why not just build dup a gsr....but then again it all depends on what you wanna do and how u wanna spend ya money.