I know there is a thread for turbo knowledge, but I couldn't get much out of it for this specifically (x-post from https://reddit.com/r/mini)

TL;DR: What turbo should I upgrade to without any additional previous upgrades?

So I recently rear-ended someone and my turbo was damaged.... but now I am looking to upgrade the turbo from the fJCW turbo. Looking around on minimania.com, I found a few different options for the N14 engine, but am a little worried about which one I should get since I do not have any other upgrades. An upgraded exhaust is the most feasible for me at the moment, and maybe an ECU flash in the near future.
Based on those things, which would you guys recommend me upgrading to?? Also, should I get a ported turbo, or no? (few example links below)
Upgraded K03 w/42mm and ported
Ported K04 w/45mm

 

I would get a refurb Cooper S Turbo or JCW Turbo. Under a grand.

http://www.jmturbocoopers.com/R55--R57--R60-Turbos.html

 

For those looking to replace or upgrade their turbo, here's the latest application guide:

http://new.minimania.com/Mini_Cooper...lication_Guide

Drive Hard. Drive Safe. Keep Grinning.