02C230C Lebanon

I need to change spark plugs for my wife's 2002 C230 Kompressor. So I went yesterday looking for Bosch "FR 7 KPP 33U+" but couldn't find any in shops in my area, but one of these shops gave me a set of Bosch "FR 8 DPP 33+" for $5 each and told me that they will work perfectly and even better than the ones I'm asking for.
Today my friend called and told me that he found a shop selling NGK "IFR 6D 10" for $9 each.
My 1st question is: will "FR 8 DPP 33+" work with my 2.3 kompressor engine? (I saw it listed for bigger engines like the SLK500 's 5.0 engine and some AMGs)
My 2nd question is: in case the shop refuses to return the money and take the set I bought, is it worth it that I would go buy the NGK set or should I keep looking for Bosch "FR 7 KPP 33U+"?
N.B.: all 3 kinds of spark plugs I mentioned have the same gap opening. NGK are "Laser Iridium", Bosch FR 7 KPP 33U+ are "Double Iridium", and the ones I bought Bosch FR 8 DPP 33+ are "Platinum Iridium", and all are without resistors.
I'd better return the ones I bought ASAP if they're not good.
Thanks in advance for any replies and excuse my bad English (it's my 3rd language)

Moviela

Spark Plug - Bosch FR-7-KPP-33U+ Bosch short number (5344) is the replacement for MBZ Part Number: 003-159-97-03-M14 (4 per car, sold individually)

NGK IFR6D10 is the NGK number for the equal plug. NGK is an OE supplier.

The R in the part number means there is a resistor in the plug. The FR 8 plug is not suggested for your engine. The gap is wider (1,0) while the FR 7 is (0,7) and the electrode is a different shape.

Try asking for the Bosch short number (5344). I would return the FR 8 plugs as not the same. I use the NGK plugs and have not had an issue with them.

02C230C Lebanon

OK. It was the 1st time I change spark plugs on this 2002 C230 Kompressor. I was able to return the (wrong) ones, and bought a set of NGK IRF6D10 (stock number 5344), and when I removed the old ones I found out that they were Bosch "Super Plus FR8KTC+" and there's another number on them "+44", and they have triple electrodes but they're not iridium nor platinum, but I should say that they were very good and long-lasting spark plugs! Had an average of 19 mpg with them till the last day (that's mainly city and heavy traffic with very little bits of highway), with a bit rough cold starting on cold weather (only some times) on their last couple of weeks. Oh, and they're cheap as I was told. Keep in mind that we don't have the best fuel quality here, and we don't have under 95 octanes (which I use).
Now with the new set, I think I should wait a bit longer before I can judge their fuel efficiency, but after around 200 miles, the average is 20. Will post some photos later and an updated mpg.
Have a nice weekend everyone!