Not all 5w30 are the same, might sound obvious but do be sure to check. 5w30 for a VQ35 will have want a different a viscosity index to a 5w30 needed in a 1.3 CDTi Combo van.
http://lubematch.shell.co.uk/gb/en_GB/browse/cars
He works for VW and its about as cheap and you'll ever find ie well less than £200 a month all in. You'll find manufactures have car schemes that side step the tax man in the normal manner
Yes pal, its not removed a smell however replaced it with a new one which isn't too bad. Would recommend for sure. I find the 350z does get smells from the engine bay, plus there's no pollen filter either.