lol 1.8 RR? I dont think they make those man...I walk LT1's all day long in my car. Even SS's. mods are in my sig.
You have the right idea with your parts list but in the long run your friend is just gonna spend more money buying parts he really needs. Dont waste money on Shortie headers. Dont get a 75mm MAF. I personally think CAI are a BS mod but they look nice and probably help our cars stay cooler in hot traffic and weather.
If it were mine id get
1. 3.73 rear end gears
2. Prom plastic 80mm MAF (cheapest but still good)
3. Mac/
BBK Lt headers, o/r h, And an SS mac catback from partshopper. 310 bucks with a rebate. cant go wrong
4. 125 zex nitrous kit
5. Trick flow intake manifold
6. FMS 65mm throttle body
7. MSD 6al Ignition (i think it makes ALOT of a difference)
Thats about 2000$ in mods and he'd probably be able to take an LS1 too
When i think about all the mods i've done to my car i regret doing so many little things and probably coulda got a turbo kit and ran low 12's without anything else. Hp performance quoted me 5557 dollars for a full kit and tune installed. But thats alot of money. So it depends on how much your friend wants to spend