Pick up a copy of the August 2003 Hot Rod Magazine... Starting on p. 48 there are "6 steps" for more power in a 4.6L... The test mule they used is a Bullit Mustang.
In brief, the steps...
1. Hypertech
2. Headers
3. Pully's
4. Throttle Body
5. Filter
6. Locker / Axles / Gears
They include $$ and dyno HP addition for the mods as singles
Step 4 and 2 were my favorites...
Don't get me wrong, these will not get you anywhere close to SC performance... But it may be something to try while I save up my shillings to get that pump.
All told... in summary...
16 to 20 extra hp.
29 ft/lbs extra trq
$2000 extra $$ for the go fast parts
Not big value... but "1", "2" and "6" may also be good for the SC upgrade... which account for ~1000
The article is definitely worth a read.
Best Regards,
_gus