Justin hi,

If you have access to Avgas 100LL use it (Although quite expensive)... It is the best choice you can get for your two stroke engine... Although Avgas is used when things on the consumption chamber are tight... Squish, compression...

If the only mod you have done so far is the HRC card well then is not necessary to go on Avgas... A good unleaded fuel will be ok... If you have started to play hard with the engine then you will have to make several checks on your engine to see if it needs to go on Avgas or not...

Is your bike a track bike or a daily use bike....?

Cheers
Michael