I was about to point out that saleens suck, but I checked out the specs on the new 281e, and they actually did a good job with it this time around. The whole engine is rebuilt now, or least the 281e is. The other 2 models appear to be plain old gt blocks.
In the past they just took a supercharger and slapped it on a GT engine, which is fine if you don't plan on tuning any further, but it seemed like a major rip to pay 48k for a saleen that maxed out around 500hp (without a major engine rebuild) when you could get a cobra for 10-15k less than that you could take up way past 600hp.