look at the specs. 100oz magnet, but they don't tell you what material the magnet is, or what type of design the sub is. 88dBA sensitivity is pathetic, really 350WRMS power handling, meaning it's low sensitivity is combined with lack of ability to handle power (weak coil windings) It also states N/A for the Xmax which means it's probably a short throw woofer.
you know instead of adding multiple cheap speakers, why not just save a bit and buy one nice sub? a good, single 15" or even 12" will utterly decimate a bunch of crappy ones.
also concentrate on using a well designed, well made enclosure.
i can speak from experience type r's are wonderful subs. they are more of a spl, i noticed they are quite sloppy but if you dont have the ear for sq you probably wont notice or care.. but they do pound hard, and they can be put in bigger boxes than most subs in their price range. i got mine brand new for $50 so i couldnt pass on it. but definitely try to up your budget a bit if you can. you say you are looking for 2 subs. but why not try a single sub set up and build a proper box built to specs. a box built to specs for a single 12'' type r will take up some space in your trunk, but it will sound better than buying 2 of the subs you were asking our opinions on.
if you want high excursion SQ, go with the type X. The type R were made to be a balance between SPL and SQ. an SQL sub if you like. They work well in a lot of configurations, and are one of the few subs to work well in for sealed, and ported settings. If you want the sub to be tight, and low, use a sealed box and feed it a solid 500 watts per 12". If you want it loud, with a bit of transient delay, go with ported, but tune it to about 32-35Hz. It'll feel deep, and hit very hard.
I like the Type R. It's a real workhorse for a very fair price.