Custom rims and tires for 2013 E4

I am having a hard time finding custom wheels and tires that will fit a 2013 GEM e4. Ideally I would like to find the largest wheel tire combo that DOESN’T require modifications to the rear spat. Any advice on where to look for wheels and tires that will fit would be much appreciated.

they are a 4x100 bolt pattern , lots of cars use that lug pattern . I have used 14" and 15" wheels on mine . I like the 15" wheels because you can put a tire on them with a taller side wall . if you go 16" or bigger you well have to use a low profile tire , looks good but a rough ride . keep you tire diameter below about 23.5" and you should be fine .I put 24.5 " tall tires on because I wanted more top speed , so had to put 1" spacers under rear fenders .you well need spacers for the rear wheels , I used the 1.25" ones from ebay and they are perfect . or you could just by the kit from ride 4 fun and its all done for you.