I'm happy with my BMR Fabrication K-member for my BBC set up.

 

I think as far room they are all similar. The UMI one does have a extra tube but I don't see where that would affect where turbo piping would go.

 

I hope your PA is better than mine was. I've seen plenty of people upset about the quality of them. Think they were mainly 3rd gens though.

Unreal weight loss claims, shoddy welds, and non fitment issues with control arms were my problems.

 

Here are the specifications copied from PA Racings website

K-member Specifications:

1.150" x .120" mildsteel 1.150"x .083 4130N Chromoly seamless DOM tubing
Any motor/chassi combo can be built (call with measurements)
Lightest Best fitting k-members on the market most possible header room
Works with stock a-arms or any aftermarket a-arms (minor modifacations required)
CNC laser cut 3/16" mounts
Formed motor mounts with optional Solid direct block mounts available
Powdercoated using the highest quality
Can be built and used on all sorts of applications including street, road race, autocross, or drag strip
Using our tubular K-member and upper/lower a-arm & coil over kit, expect a weight reduction of up to 85 lbs. Combine this with a Santhuff or Afco spring/shock combo and a lightweight Pa Racing rack & pinion kit and front brake setup and lose over 150 lbs. off the front end!
Grade 8 shock mounting hardware Available (extra)
Fully assembled and ready to install
100% jig welded! All parts are Jig built in-house!
Made in USA with best materials available!
STRONGER, and LIGHTER than stock! (loose over 75lbs)

I highlighted the weight loss in bold. I'd like to see you loose over 75 lbs by just chaning a k-member. It just isn't going to happen because the stock k-member doesn't even weigh that much.

 

I've only used 1 PA k-member. It was in for a SN95 Stang and it fit like a glove with great welds and quality.

 

Yep it is impossible, the stock K-member only weighs 57 lbs

 

my stock K member was 54 lbs, the PA racing one I got is 22 lbs so I lost 32 lbs with the K member, I lost another 8 lbs with the tubular upper and lower A arms, those are spohn's, so 40 lbs off the front end but thats still no where close to what there saying.