I'm not going nuts on the modifying but I also am not thinking about how "worthwhile" it is. I want the go to go faster and be more fun to drive, cool. I'm prepared to spend the money to put an RB25 and anything else I feel is warranted to make it go faster. It is a personal preference thing, I am not planning on selling the car anytime soon and will not be expecting to get back any of the money I have spent on modifying when the time comes to sell (not that I think that time will ever come ).
Basically, if you want it and you can afford it, do it.