First off Toby are you at Cov for the last MAM? If so please pop over and I will go through the car screw by screw with you, not many people in the UK that have run ZX5s longer than me! My car has a few "tweaks" on there which can be done in a couple of minutes, nearly for free and make a great car unbelievable!
The broken front tower issue USED to be a real pain in the bum but I've <runs off to cuddle a tree> not broken one in 2 years now.
There are a couple of tricks, all found the hard way (and repeated at the rear of the car just to be certain);
1) The screws which go through the tower mount and gearbox top into the lower trans case are FAR too short in the kit. I run 20mm cap heads (less likely to round than buttons) through there, you may find that you need to shorten the screws a fraction or space under the heads a little as they can touch the wishbone and bind it up!
2) The single screw that connects the tower mount to the gearbox top makes the assembly too rigid, I have an O-ring between 2 washers on mine, just nip it up so the o-ring compresses and it locates without being solid.
3) Shock screws need to be reversed. Use button head screws so the button is forward .. order is
screw head - shock bush - (spacer if used) - plain nut - tower - washer - nylock
this has the added benefit of making it much quicker to change upper shock positions
(note:- if you do the same at the rear with the shocks on the back of the wishbones as I run them make sure you have near zero thread showing past the nylock!)
4) Tower choice, the LA216B (4 hole tower) is now available and has extra material in the webbing ... not seen one of these broken (yet)
Now I use the ali 3-racing tower mounts but if you want to them remember they are 1.25mm shorter than the FS/FS2 mounts so will need spacing up. I actually have 2.25mm under mine as I find the car realy benefits from having the extra up travel that raising the tower by 1mm and lengthening the shock shafts by 1mm too gives ... so much more consistent on heavy landings, especially if you have to have lock on!
In terms of strength my car is basically an FS2 now with the LA216B tower, aluminium rear hubs and 3 racing ali tower mounts and it's strong as hell. I can only remember having 2 breakage related DNFs with the car in the last 12 months, 1 was a front kncukle set (on a MASSIVE jump at Ardent) and 1 a rear shock shaft after being hit full wack by an Ansmann X4. The others (about 6) have all been the same thing ... wheel nuts giving up!
With the original tower I used to run a GRP brace from the damper bolts down to the tower mount bolts on the rear of the tower but I don't feel this is needed with the LA216B towers, also as Nick says either a brace or a carbon tower (unless cleverly designed
) will just transfer the loading to the next weakest area ... always more expensive and harder to change!