dedlyjedly wrote:if so, the rsd 500.4 will give you more power than the x100.4 when bridging a set of the channels
r500.4 Xenon equivalent is the x200.4, the x100.4 is more like the r300.4. When you compare like that, things seem much more favorable to the Xenon side of things. The 200.4 is not what dragon asked about though, so I am getting a little off track here. Between the X100.4, R300.4 and R500.4, the R500.4 will be the most powerful, by far. The Xenon wins out on features and future usage... swap the stereo into a new car, and the system may change a lot. However, the amp can still manage a wider range of loads, so has a higher probability that it can still be useful, even with a completely different layout.
dedlyjedly wrote:third option.

a ti500.4 would perform very similar to the rsd 500.4 while adding an lpl port. I also believe Tom has experience running the rear channels of his ti500.4 into 2 ohm mono loads. It also has greater crossover versatility than the rsd making it more flexible for future system configurations.
This is hands down my favorite PG amp (along with ZX450). It's small, robust, can power a whole system, and has all versatility you can imagine. Run a whole 3 way active system off of it (tweeters, mids, sub) all off one RCA using the same crossover. Or shit, install it somewhere awkward like
under your parcel shelf 
. With the amps as cheap as they are, they are a complete steal. Despite that it sounds like not a lot of power, it can
kick your ass, whether at 2 ohms or 4 ohms bridged.
dedlyjedly wrote:or if you've got the room, take bdubs advice above. due to the extra power for the sub (let alone headroom for the components) this option trumps all.
Seconded. X200.4 is ultimate if you can fit it.
Now that I think about it, Xenon should have been released as Ti Elite amps, with a much more rugged chassis. The X200.4 would power an Elite 9-5-1 set perfectly, with the X1200.1 being a great match for the Elite 12D. The Xenon speakers didn't match the amps nearly as well IMHO.