Narrowed beams can come in several different configurations. A German beam EMPI adjusters (China) are welded in at the same time to give you adjust ability. Some companies retain the factory bearings and bushings others use urethane bushings from either EMPI (China) or Bug Pack (China). Another version is to buy new materials including mild steel tubing boxed tubing split in half for beam supports EMPI (China) adjusters urethane bushings (China) and plasma cut shock towers that bend around the body. The last possible application is to use all new components only using product machined or made in the USA. We will break down each possible alternative.

GERMAN BEAM -

Using Original Beams- This is in-expensive but to ensure a good beam make sure they hot tank the beam remove any and all bearings and bushings jig build the beam re-enforce the shock towers use quality hardware check the torsion for wear or weakness. If all these aspects are done a German beam can be great.
Empi Adjusters $12.95
Core beams $100

NEW MATERIALS including EMPI (China) Parts

Mild Steel Tubing - Inexpensive and not always a true due to it having a seam.
Cold Drawn Welded (CDW)
Produced from a steel strip by cold forming electric resistance welding (ERW) and cold drawing to finished dimensions CDW is the most versatile and widely sold mechanical tubing grade. A variety of thermal treatments can be applied to alter the mechanical properties and machinability. CDW is used for a tremendous variety of machine parts where close tolerances and higher mechanical properties are needed. 58000 PSI tensile
Typical Applications:
Automotive components shock absorbers hydraulic cylinders sleeves bushings axles and shafting.
Wikipedia
Price per foot $5.17
Empi Adjusters (China) $12.95
Empi (China) Urethane Bushings $30.95
Shock towers plasma cut & broke in two places $12 each $24 total
Upper Shock bushings $7.50 each $15.00
Parts Total $126.87 EST
Welding a total of 22" = 30 minutes
Prep & paint 20 minutes
Install Bushings 5 Minutes
Retail Price $300 EST plus fees

NEW COMPONENTS MACHINED IN THE USA
DOM Tubing
Drawn-over-mandrel tubing is made from cold-drawn electrical-resistance-welded tube that is drawn through a die and over a mandrel to create such characteristics as dependable weld integrity dimensional accuracy and an excellent surface finish. This process called cold drawing may be repeated more than once to reach the planned OD ID or wall dimension. Multiple draws can also be used to increase the strength or improve the surface finish of the tubes. During the drawing operation the tubes may be process annealed to increase the ductility of the material. Lower cost alternative to CDS with equal or superior physical properties. Compared to structural pipe DOM Round Tubing is produced to more exact OD and ID tolerances and better finishes without a seam. Ideally suited for a wide range of structural and bushing applications. Widely used in stressful applications requiring higher quality uniformity strength and soundness.  80000 PSI tensile.
Wikipedia
Price per foot $9.94
Chromoly Broached Adjuster centers $22.50 each $45 total
Slider bracket $6.75 each $13.50 total
Billet Slider $ 4.75 each $9.50 total
Zinc plated hardware $5.00 total
Zinc plated zerks $4.00
Laser cut bent & welded beam supports $17.50 each $35.00 total
Body bungs $2.75 each $5.50 total
Delrin Bushings $25.25 each $101 total
Steering dampener bracket $6.50
Laser cut bent & welded shock towers $24.75 each $49.50 total
Parts Total $334.14 EST
Welding a total of 52" = 1 hour 25 minutes
Prep & counter sink shock tower holes  30 minutes
Install Bushings drill & tap for zerks 20 Minutes
Retail Price $415 EST