Strut brace for the 20VT has to be the standard Sparco one really. It has kink to get round the brake fluid reservoir. You can get it from your Fiat dealer or for Alternative Autos.
Dump valve - you have a wide choice. Decide whether you want recirculating or not. Bailey DV30 and Bailey DV36 seem good examples of each. They don't make too much difference though, unless your standard dump valve is broken.
Exhaust-wise there are a few options. The Supersprint exhaust used to be popular, but there are now 2 common options from Blueflame and Milltek. I had the Milltek. it was good. It cost about £350.
H