If I added up the purchase price of my DE, plus all my mods, both the performance and rice, I'd just be into 370z money. Would it have been more sensible to get a more modern, more capable 370z for the same price. Yes! Do I wish I'd gone straight to 370z? No! I'd have had to wait longer to become a Zed owner and this is the first car I've modified, so I've learnt loads and it's been fun.
I think you'd be mad to spend the money going from a DE to an HR, unless perhaps you wanted to switch from a coupe to an roadster. All IMHO. I'd go 370z.