just do the conversion, make its clean and presented in a professional almost factory way and 9 time outs of 10 you'll never worry. if for some reason you do get in trouble then talk to the engineer then. no point wasting time and money for something that may never even be an issue in the first place!
If most of the parts you bolt on or upgrade with are nissan items and factory trim (no crazy retrims on seats etc) there wouldnt be many inspectors that would be able to tell the difference from an initial glance