welcome along bud.
150s are standard 1.8Ts, 180bhp were the anniversary models with lips on the bumpers and sideskirts. same engines, different maps. anni's tend to be a fair bit dearer tho
close but no cigar. the 180bhp (AUQ code) engine in the anni was also used in standard 1.8T's from late 2002 onwards. it was just a slight software change (remap) from the AUM 150bhp golfs (2000-2002). there are earlier engines..
AGU (up to late '99) - K03 turbo, no VVT, Non DBW, 150bhp, 5speed
ARZ (99-00) - K03 turbo, no VVT, DBW, 150bhp, 5speed
AUM (late 00 - 02) - K03s turbo, VVT, DBW, 150bhp, 5speed
AUQ (late 02 onwards) - K03s turbo, VVT, DBW, 180bhp, 6speed
check the mk4 section for remapping guides etc.