I'd say keep it since original lip is hard to come by and it's freshly painted. Brand new is over $600 a pop!! The cheapest knockoff Mugen lip is only hundred plus so just get it and save the CTR lip as a spare. You might get tired with the Mugen and realize that the CTR is better. It's original lip after all.
Tried to search for threads with regards to the Skyline 250GT but could not find any. Am looking to buy this car but need more info on it. Appreciate if any of you guys can share any info related to this...