Get a known brand which has proven performance,whiteline bar is 22mm which i think is perfect i dont get any oversteer very neutral, 24mm would definitely give you oversteer.
$500 is about right, mine cost me $520 Fuel filter is under back seat Log book servicing is important for resale you will get more when you sell and pretty much any mechanic can stamp log book but they wont stamp it if you have done service yourself
I have had my sportivo 3 months now and i noticed the same thing with mine,i fixed my tapping noise with a good oil flush like ENGINE DETOX Liqui Moli AND CHANGED OIL to a good Synthetic oil and it fixed that pesky tapping sound.