HAHAHAAHAH nexon... nexon..

Couple more levels...
6514 at 48 (295+79 INT) / +2190
6609 at 49 (301+78 INT) / +2190
It's giving me less INT as I level, probably cause I'm a Blaze Wizard and it doesn't expect 6 AP per level... Currently at +75 INT/LUK, +2190 MP, +300 HP.

I've noticed that the number of points added to the lower sidekick's main stat seem to be determined by a formula that goes something like:
[(higher sidekick's level - 5) - (lower sidekick's level)].

I'm not sure about the secondary stat yet, but that formula seems to work for the main one.

Edit: Never mind, I just went on a level 33 Thunder Breaker and had him be the sidekick of a level 92 Sniper, but the Thunder Breaker gained 110 strength and 40 dex from the sidekick buff.