I don't believe Alpina had any involvement in manufacturing the engine. It was their design, but BMW built it on their standard line.

I have read conflicting information on whether the heads were ported and polished. These Alpina owners say not.

X5 4.6is engine - Alpina or BMW - The Unofficial BMW M5 Messageboard (m5board.com)

I wouldn't expect different welding processes given the limitations of the X5 assembly line.

Your list of options may apply in the US, but each market has different configurations. If you are going to list options that were included you need to make it country-specific. Perhaps BMW in the US added CWP, but in Canada even the 3.0 had it standard.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue