If you don't like metal on an average system, using a better audio system is not likely to make you like it or appreciate what a better system can do.
It is like playing in the sand. If you are averse to playing in the sand and getting plastered with it on your skin, you are not going to appreciate going to a beach with finer sand.
Metal can actually make good test music for your audio chain to expose some deficiencies which might not be caught otherwise in auditioning. Unless the genre itself makes you run screaming from the system...
One thing that people have not mentioned. You need a good soundstage resolution and width in your audio setup. Electronics or speakers or placements of speakers that compress the sound stage is going to make the incoming wall of sound incoherent. Spread it out well and you can hear the interplay between instruments and the grunge is not going to dominate/mask everything. Because it is high dB sustained over a larger frequency spectrum, many things in the audio chain can start to muddy the sound stage or be unable to resolve individual pieces.
While Metal is associated with distorted sounds, it is not any type of distortion. The popular amps and effects units used are known for shaping the harmonics introduced in ways that don't sound bad (which is different from some people finding the genre itself annoying!). Companies like Electroharmonix have made a lot of money perfecting distortion and could probably teach Nelson Pass a thing or two.
I don't play metal, but if you spend a lot of time playing with distortion units for a guitar to get that right Hendrix tone or the Gilmour tone, you get a good feel for what kind of distortion/harmonics works and doesn't. It has also made me a lot more sensitive to hearing unwanted distortion in the audio system even very subtle ones. So, if the metal music induces quick fatigue or harshness that makes you turn down volume (as opposed to getting a headache from high wall of sound which is not unusual), there is a high likelihood something is not right with your audio system in tonal balance or distortion.
Unfortunately, for a lot of people their first exposure to metal is likely to be with poor audio over a radio, or an outdoor performance with bad PA or a mediocre audio system (metalhead friends have a poor correlation with having a lot of money to buy good equipment) and just like with Opera, put them off for a lifetime.