Starting my Project on 91 Lx need help!!!!

Ok so im in Afganistan and i just bought a 91 Lx 5.0.. ON leave i went in and Talked to Mike Murrilo mustangs of San ANtonio and they gave me a quote on a 306 R block built from the block up to the intake with a Vortech tune and install for about 12,500 how does that sound? Everything he said would be forged afrs 205 typhoon intake etc.. My question is before i send it in for that what supporting mods should i get on the car first? I know i need brakes Ive been looking at getting a cobra R brake kit from Brothersperformance.com.. Or if i didnt go with a new motor the original has 160k would a HCI package be worth it? what kind of numbers would i be lookin at? Mike murillo said with that set up they want to built i would be making 500 safely... Anyways much help would be awesome with all of this... Heres a list of whats already on the car...

Engine:
E-Cam
Ported E7's
Shorties
O/R H
Flows Dumped
BBK Intake Tube
A/C and Smog removed

Drivetrain:
Freshly 3.73 Rear end by Strictly
About 2k miles on a rebuilt T-5
King Cobra clutch
BBK Pro Ripper shifter
Aluminum D/S

Chassis:
BBK Subframe connectors
Sportline front springs
BBK Drag springs in the rear
FRPP C/C Kit
New Koni shocks

Wheels:
17x9 03-04 Cobra wheels
New tires on the front
About 75% left on the rears

Audio:
Alpine head unit
All aftermarket speakers
10" Rocford Fosgate
800w Amp

Body:
Salaen Spoiler


Miscellaneous:
Battery relocated to the hatch area
New Carpet
New shifter bezel/Boot/Knob
Clear Headlights
Shorty Billet antenna
New door handles
3G Alternator

Yea im from San Antonio, I actually live out near Medina lake.. 2011 marks the year i get out of the army and move back i cant wait! ANyways yea it seems kinda steep not sure i want to put that kind of money in my car... Is it possible to get 320 hp with bolt ons?

Hey thanks for all the good feedback... Ive been talkin to some buddies back home and there saying just buy an 03 04 cobra if you want that kind of power. So Ill probally just do basic bolts on.