Structural Question, crossmember bolts in sheer or tension? Options

[cooler]

hello 914 structural experts,

I am planning to create a new crossmember to stiffen rear suspension and support engine. The 914 rear suspension console is well known to flex under racing stress and was reinforced by factory racing teams. I intend to address the flexing issue and create engine (Audi V8) mounting locations with a new crossmember and diagonal tension members. The attached photo shows the location of crossmember (red) and diagonal tension members (blue).

The crossmember spans between the suspension consoles, on center with the trailing arm pivot axis. The diagonal tension members span also from rear suspension consoles to firewall, near center tunnel. This assembly will need to be removable to facilitate engine removal and is intended to stiffen the entire engine bay/rear suspension.

I am struggling with detailing the crossmember bolted connections at suspension consoles. I assume each connections should include two bolts each but, should the bolts be loaded in shear or in tension? What size should the bolts be?

Thanks in advance

[cooler]

Thanks for your input,
Stressing the engine as a structural member raises a couple concerns. 1. Will the engine withstand these forces and fatigue? Will the engine vibration transfer into the chassis, fatigue chassis components and occupants?
The term semi-stress is not clear. Does this means some kind of structural insulators incorporated? If so will the insulators effectively transfer stress and resist deflection?
My objective is to support the engine and stiffen the rear suspension consoles.

I have started fabrication of a crossmember using 1 3/4" .125 tube (pic below) but it looks kind of wimpy, especially with the drop in it. I want it to be stiff not just strong. So I'm thinking upgrading to 2x3 .120 tube. The diagonal tension members are also shown in pic, 3/4" swaged tubes from Speedway Motors with 1/2" rod ends.
Let me know what you think
Thanks