To get it "right" in my book was to NOT fit too wide wheels & tires. And i DIDN'T spend much to get (keep) car that way
.
+15 .. hmm, maybe some longer studs & spacers can help .. of course prior purchasing one should check if that's right spacer thickness, and also if rubbing won't start at fender. And you wrote that you don't want spacers.
There is also option of installing wide body kit in addition to spacers.
But in general my advice would be, if those wheels are required, - to eliminate need for airbags - reduce drop and back some ride height back (most probable reason why you thought about them, right?). This way you'll gain back daily practicality going over roadbumps/steep driveways, and suspension will actually have some travel (especially in rear) to be actually able to work to soak road imperfections/add comfort/add stability/add grip/add daily driving compliance.
Or sell those wheels and get something more sensible. x8 if your care about weight and nimbleness, wider, only if you need extra rubber for auto-x due some class limitations (which i doubt, as rarely stance/drop people do auto-x or HPDE).
Or better - both! Both reduce drop and saner width wheels.
If you did wide wheels and extreme drop due your friends thinking "it's cool" .. imho those are "wrong friends"
, as making car worse and paying lot of own money for that + keep buying stuff to "fix/bandaid" problems such decision brought is not cool in eyes of sane persons