Infinity has 1" tweeter. MB has 3/4".
Both use polypropolene cones w/a rubber surround. The Infinity uses a Silk tweeter. MB uses Titanium.
The Infinities are rated at 67 - 21k Hz. The MBs are 52 - 32k Hz.
The Inginity's sesitivity is 92. dB. The MBs are 85.9.
The Infinities need 2-75W RMS. Peak is 225W. The MBs need 40-100W RMS. Peak power is not listed.
So, the answer to which is better depends on your answers to these: Will you be using a powerful amp? How much can you afford to pay for one if you don't alreayd have one?
If you don't have amp already capable of playing at least 50W (or funds to buy one) I'd forgo the MBs. The Infinities would be much better suited to the power supply of an aftermarket HU. You could still put the MBs in, but they would take alot of power you don't have trying to play loud and you wouldn't hear them anywhere near their full potential. In fact you would be underpowering them, which is one of the quickest ways to kill a speaker.
That said, with the propper power supply, the MBs win w/ only one issue. The frequency range is far greater than the Infinity. The onty issue is they have smaller tweeters. Other than that, with the propper amp, the sensitivity doesnt matter and you're golden.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>