Markbass Nano 300 & Traveler 102P Cab - 8 or 4 Ohm best?

Hi all.
Yesterday I purchased a Markbass Nano 300 Head and the Markbass Traveler 102P cab in 8 ohm. I`m really on the fence about keeping the current 8 ohm cab or exchanging it for a 4 ohm one ( they did not have any 4 ohms in stock to compare anyway)
I`d like to keep the option open of adding an additional 8 ohm 15" ect. occasionally. I like having that option for the future, but..
The questions, will I sacrifice a lot of volume loss and character/clarity ect. in 8 ohm compared to 4 ohm in the cabs performance? (The head gives/takes 150w in 8 ohm, 300 in 4 ohm) .Will there be a huge difference in the Nano 300 head`s performance and undermining its full capability? Any suggestions would be appreciated. I upgraded from a Trace Elliot 300w gp7 with a 15" so I just upgraded from the middle ages..
Thanks so much in advance!
 
will I sacrifice a lot of volume loss and character/clarity ect. in 8 ohm compared to 4 ohm in the cabs performance?

Short answer, no.

Will there be a huge difference in the Nano 300 head`s performance and undermining its full capability?

No.

I`d like to keep the option open of adding an additional 8 ohm

A good plan there. You will get much more by using two 8 ohm cabs, than using your full power with only one 4ohm cab.