Hi i have a mk3.5 (P reg 1996) 1.3hcs CFI fiesta
Not going to try big it up much it's slow as fuck ! just about crack 115mph down hill (Clocked on satnav my speedo was only showing 100mph)
I have fitted SI bumpers, and full SI spec interior
Rose jointed lower arms
Polly bushed everything possible with the "Cheaper" Floflex bushes
have GAZ adjustable shocks and 60mm Fiesta center springs to put on it
And currently search for a set of 15" escort GTI wheels to paint white and put it on
Not going to tune this engine as it's simply not worth it, in the near future it will get engine conversion
(1.6 silvertop on bikecarb/ESC setup)
But in the mean time i want to make the handling the best i possibly can, thing's i don't have that i think will help my handling are, Front upper strut brace, Rear Anti roll bar, Weld a plate or some box section in the open /under side of the rear beam to increase rigidity ?????
I have only had a quick look and can't see any kind of mounts for a rear ARB can my rear beam have one ?
And could anybody that as done the welded rear beam mod let me know how they did it - What they used - has it made noticeable difference on trackdays and back lanes ?
Cheers kieren
P.S any other suggestions to make my car handle even better much appreciated
the thing was a pure go-kart! well recommended mate! 
only thing i would recommend is if you weld it, get youself a lower s brace as its so stiff that the shell sarted twising in hard cornering 
but the s brace helped that
looks like i have to just do the weld mod and live with that