Fox 34 Unsure what to do??

I recently bought a Yeti SB66c which I have steadilly been upgrading (a little). It came with a set of Fox 36 RLC factory forks from about 2013 which seem okay. Trouble is after a few beers a few nights ago I decided to order up a set of 2015 Fox 34 150's (which the bike is designed for) from chain reaction due to them being heavilly discounted (along with the 15mm hub adaptor for the easton haven carbon rims on the bike). After a little (sober) hindsight and digging I have realised that to get the best out of the new 34's I should really replace the air spring with the newer version found in the 2016 version at about £135 ............ Or I could just send them back and stick with the 36's???
I really don't know what to do??? I have held the forks up against the bike and there is a considerable difference in axle to crown height and I cant help feeling the 36's are slackening the bike off to much and I should go with what Yeti designed the bike for (after all surely they know their onions when it comes to bike design!)
What should I do??
What would you do???
Help!