No one here is mentioning the huge aftermarket for LSX engines. I've been going to Capitol Raceway for years and the only way I've seen to make the new Mustang fast is a Procharger or N20. I'll take the Camaro (which is faster to begin with) with it's endless supply of heads, cams, and simpler SOHC design.
The aftermarket for the venerable Windsor (302/351W) (of which the LSx borrows MANY traits) is far larger than that of the LSx series. Probably the largest of any engine family now, including the old SBC. I would hardly call the aftermarket for the LSx engines "endless", it is a market that is far smaller than for that of its predecessor.
The Modular engines don't have a huge aftermarket following, but the 4V heads, from the Cobra, Navigator, Aviator and Mark VIII, worked, will flow over 300CFM (324/263 for the '03/04 Cobra heads) at only .500 lift when worked by TEA. This matches the flow numbers that require .600 lift on the LSx heads with the same Stage 3 port job.
The '03/'04 Cobra is also faster than any F-body ever produced, and will handle 1,000HP on the stock internals with ease.
The new Mustang is also available in GT500 and GT500KR trim, again, faster than the last F-body in ANY trim-level stock. And yeah, it comes with a blower too and forged internals good for over 1,000HP stock.
Not to mention the massive following the Mustang has, which is why it is the only car with its own racing league, the NMRA.
Now that Government Motors' financial train-wreck has come to rest on the loins of taxpayer, I anticipate the return of the Camaro to short-lived.