1st off, I think this thread is better suited in the tuning lounge:
Tuning & Upgrades - Alfa Romeo Forum
You will not get past 170km/h on most straights on a with reasonable Normally Aspirated mods on a 2.0 motor. Down Kyalami's mineshaft I reach just over 160km/h , at the end of the main straight under 150km/h. I have never used 5th gear on any racetrack (Kyalami, Zwartkops, Midvaal, Phakisa) So a closer ratio (lower geared) gearbox is better.
The 1.6 ECU cannot drive the variable length inlet manifold, so yes the 2.0 ECU could help with that.
1. Loose weight in the car - it is the cheapest way to go faster. I stripped my 156 racer down to 1080kg and GTV racer to 1090kg. Then work on handling: 1: Semi slick tires, 2: track / race grade brake pads 3: coil over suspension: drop a slight bit and stiffen up the rear
2. You have the 2.0 throttle? Why do you want to go bigger throttle? It does not equate to more power. If you redesign the whole intake plenum, then sure go bigger throttle, but for now the OEM throttle is perfectly matched to the OEM plenum
3. On cams: http://www.alfaowner.com/Forum/tunin...of-timing.html (Ts camshaft gurus. A question of timing...)
That will be your best bet for increase in power, but still no major differences - I'd rather spend money on brakes and suspension, maybe even a limited slip diff (Quaife makes one for the TS box)
4. As long as you can get hold of the non-cat exhaust headers of the 2.0 - you will not gain too much
5. You mean the whole intake manifold as question 2 talks about the throttle? I'd leave it stock, but get the 2.0 ECU to manage the variable length.
6. Only if you boost: Turbo / Supercharge / NOS will you need bigger injectors. For Normal Aspirated : You have the 2.0 injectors on? If so then fine.
7. Plug-and-play performance chips make big differences on turbo cars. You need to get a tuner that you trust 1st, then use the chip he can tune well, there are no plug-and-play chips for N/A cars worth the money.
So to recap... Spend money on handling rather than power... Go have fun 1st... only later add power
On my local race track (Zwartkops) I managed 1:19.2 with a 3.0L 156 with road weight while I managed 1:18.0 in my 2.0L 156 stripped out racer. Both on Semi slicks, both on coil over suspension. Weight reduction means much more than more power