I had 2 12 xfls in a 4.5 cubed box tuned to 32 hz on a audioque 2200 and they were really surprising. Got loud got low and sounded pretty good as well. I had a crap electrical system at the time. No spare batteries and a stock alt and no big 3 upgrade. I beat the crap out of them and the guy I sold them to still has them with a similar crappy electrical system. He still beats the crap out of them and they have been abused for about 2 years now. As far as type r's go. I've never personally had any but seen a few people with them and they didn't seem awful. I'm just not a huge alpine fan but that's just me.. Its a shame you can't get a SSA sub. I have a 12 inch zcon on a crescendo bc3500 right now. This single sub gets louder and lower than both those xfls did and sounds great to boot.you might also look into some fosgate t1 or t2. I had some of those and they were pretty impressive but you don't want to over power them or Clip them at all.If I were you I'd try to find some used stuff first or see if you can find people with different sub setups so you can check them out.the worst thing you can do is watch YouTube videos. Everything looks good on video lol.