I'm not sure which part you want comments on, so I'll make a few general comments.
1. The top of the shock tower, and the inner fender well were never designed to be load bearing. So as soon as you turn the suspension into a "coil over" set-up, it will be a "flexy flier". The sheet metal and "shock tower" will flex all over the place.... foreward under braking, up/down over bumps, and side ways under cornering.
2. The "strut brace" between the two shock towers only helps a little. With the brace the flex is shared between the two shock towers... now they both have lateral flex under hard cornering.
3. A 1.5"x.095" "1020" (roll cage material) tube that connects back to the roll cage fixes the foreward flex under braking, but does little for the lateral or up/down flex.
(Note that what I am talking about here is flex under hard core racing conditions with racing slicks etc. Using regular street tires might be OK.)
We designed a "kit" a few years ago, that fixes the flex. The problem with the kit is that it is like all racing stuff... very expensive. (Figure on at least $4k by the time you're done depending on what coil-overs you choose... we went with Koni's @ $550 each not including springs and hardware.)
After we got done with all the time, effort and aggrivation, the only advantage we ended up with was adjustability. And the reality is that once you've got the set-up, it never gets adjusted. (We changed springs and shock settings from track to track.) So, as it turns out, if you have adjustable shocks (non-coil-over) and a couple of different springs, you end up with the same thing... for a lot less $... but a lot more "pain" changing leaf springs.
In the end, when I "crunched" the car with the coil-over set-up, I went back to the leaf springs... and then on to win a National Division championship.
So, I guess my best advice is that unless you are going to go racing in the GT4 class, stay with the leaf spring. If you're going GT4, then cut off the front end at the fire-wall and tube frame the whole front.