Just my opinion for what it's worth....I have used the 'cheaper' chrome items on previous vehicles and have always regreted it.....the chrome started to dis-colour very quickly; especially on chrome exhaust tips......the old saying, you get what you pay for
I've had the BMW OEM's on the Zed for 3 years now, with no problems.......just an occassional wipe over with chrome cleaner & spray of WD40 for good luck......still look like new.
I just think it will be worth saving the 20p's.....with no regrets
Good luck with your search