Does anyone know what issues i might face by swapping my 33 inch mtr tires for 35inch Mtr's?  

Can't help without knowing which Jeep you have and what you've done to fit the 33s.  Wish I had the dough for 35" MTRs!  

in an xj (cherokee) you will need at LEAST 5.5 to 8 inches of full lift W/ fender triming and all that junk!!

in a wrangler type, 35's (depending on modle-cj,yj and so on) a total of 4 to 6 inches of lift is required although I would not sugjest more than 2" of that lift be body type!

on bolth plains wrangler & cherokee's unless you have an old school bruiser w/dana 44's youre gona start snapping axle shafts if you wheel the machine and you will also be snaping them more readly on pavement too if you are a fan of "the stuipid petal" unless you have access to 44's WHY ARN"T THEY ALREADY UNDER YOUR JEEP!!!! LOL! any way there are aftermarket chrome moly axles for dana 35's &30's that for the most part drop right in and can handle the tork required for 35's unless they are over 14" wide then cornering on dry pavement will still cause reason for concern. you may also want to upgrade your steering box and brace the frame around it as well as reinforce and brace it TO the frame especilly in an older 80's wrangler type and in bolth rigs you will be hiting the rear fender on full stuff so WHEN not if you trim the fenders try not to trim but to "fold" the rear fenders in to prevent cut catch and gouge pointand preserve the rubber for the trail not the rig!!

After reading the first two responses I don't think that people know how to read.

Swaping tosmaller tires is a no brainer. Go buy them and put them on. Your engin RPM will pick up a little. 

I read, "...swapping my 33 inch mtrs for 35 inch mtrs."  The word "my" tells me the poster wants to go up in size.  That's what it looked like to me, anyway.

...and I THINK he owns a "blue TJ"...  

Ok if its a TJ with 33's swapping for 35's. If you have a 4" lift you can fit 34's with out any modifications. JP put 35's on a stock wrangler, but had to cut the rear fenders and put a Rock Crawler Hood on.  

Well, maybe he does have a blue TJ...But maybe he wanted to put the tires on his uh, um, DJ-3A?   

Sorry! I can't read. Must have tired. Just put the 35's on and see where they hit. You allready have to have a lift for the 33's. You can add coil spacers to your blue TJ to fit the 35's.