dont the factory eaton supercharged versions have a bypass valve(like Saleen/Roush/Magnuson)? if so I think the mpg impact of the blower might not be that great...under boost the blower will suck, but bigtime difference with the 'flywheel in a vacuum' drag that the bypass valve allows...what I'd personally rather see is the v4 highway mode cylinder cutout- my wifes new Avalanche has it, and its not noticeable- but it does get pretty decent mileage for a truck...bet the mustang highway mpg could go up 15~20%, and pretty darn sure all it would take is a new tune to implement it- the cars already supposedly have the alternate firing ('4cylinder' mode) for dry running(copied from Caddy Northstar I believe), so why not just reprogram it to come in at light cruise like Chevrolet did???

 

Well S/C'd motors are notorious for running fat A/F fuel ratios to keep things cool and there in lies the problem, even with a bypass - which helps to keep the charge cool and I think also helps with parasitic horspepower loss - you still have to keep the A/F ratio fat to avoid detonation (the compressed air is still hotter than ambient).

It would be nice if Ford offered AFM on thier V8's, originally I thought that OHC cam engines were unable to do this trick, but if you take a look at Ford' system, it would easily lend itself to cylinder deactivation since it uses a cam follower (essentially a rocker arm) and a hydraulic lash adjuster (think hydraulic lifter) sitting opposite to the valve with the cam lobe about in the middle between the lash adjuster and the valve. Cut the oil supply to the lash adjuster and give the cam follower enough room to drop away from the cam lobe and the cam cannot act on the follower which in turn cannot act on the valve.

 

If Ford want an economic Mustang why didn't they install the 2.7 liter 24 valves twinturbo Jaguar diesel engine? Jaguar says:
Jaguar´s 204bhp 2.7 litre twin turbocharged diesel engine features advanced technologies including the latest generation high pressure Common Rail direct injection fuel system and a lightweight Compacted Graphite Iron (CGI) cylinder block. It delivers enormous reserves of torque for swift and smooth overtaking, and offers improved fuel economy, and low emissions comfortably within the latest Euro IV requirements.

Specs:
204 HP of power
320lb-ft (435 Nm) Torque/ 80% of max torque available from just 1500 rpm!!
Performance:
0-60 mph in 7.8 (in Jag XJ) it will be 7.4? in Stang
mpg urban-extra urban combined with automatic:
35.0 in XJ / 36.0 in S-Type and 45.6 extra-urban !!!!!
or with manual
41.5 mpg combined.... Guzzler Tax?????

Ok you won't have the nice burble of a V8 but it's a powerfull engine with a lot of torque...

If Ford want a V8 it exists on the Range Rover:
3.6 liter V8 32v turbo diesel:
271 Hp and
472 lb/ft of Torque
mpg 25.0 (combined) and 31.2 (extra urban) in the Range... ilt will be a lot better in a lighter Stang