I'll give you a few tips along Mosca's "I wasted $20 so that you don't have to!" advice.
Black 2003 Audi
1) First I tried #26. Good stuff, but had nothing to compare it to really. Did about 3 applications over 2 months. Happy with durability, shine and depth were okay. Definitely a lot of residue.
2) After hearing a lot of good stuff about Blitz wax, switched to that and also incorporated IHG and GEPC into the routine. IHG was pretty good, GEPC was incredible (still my favorite product). Topped with Blitz. No we're talking. Great shine, great depth, great durability.... until....
3) Realized that the Blitz attracts a hell of a lot of dust and was staining my black trim. Also noticed some dealer installed swirls that were finally coming up after a few months. So, added SMR to the routine, replacing IHG. But after applying by hand, I realized it was pointless. So I bought a PC.
4) Now I got the routine down to tackle my swirls (SMR w/ yellow pad and GEPC w/ white to bring out shine), but what will I top with. Did extensive reading on this board about Klasse and was leaning towards that, until I read some stuff about Poor Boy's. Klasse seemed to be a little temperamental and there were a handful of remarks about the bling bling capabilities. Not to mention it didn't seem compatible with my beloved GEPC. Poor Boy's seemed to have the shine, the ease of use, no compatibility issues, maybe some questions about durability. Since I wax and work on the car often, I don't mind the durability issue as much, so I went with Poor Boy's EX and decided as topper to use S100 wax.
5) Used the PC with SMR got out 80% of the swirls and little scratches. Applied three coats of EX (WOW, 2nd coat brings out incredible shine) and topped with S100. Now I maintain with S100 coat every few weeks and maybe a QW after weekly washes.
6) Next steps. I've continued my reading on Klasse and seen some incredible "shine and depth" pictures and feel comfortable giving the twins a try now, having learned some trade secrets. I'll wait till I use up the EX (because I have no problems with it) and then go the AIO, SG topped S100 route. Using SMR and DACP (depending on how bad the swirling is) to clean up the paint. Still have to figure out a way to work in my beloved GEPC.
Anyway, that's my 6 month detailing story. Hope I saved you about $600, because that's what I've spent so far.
P.S. I didn't mention any applicator, towels, drying mechanisms... otherwise this post would be a few more pages long. But to make a long story short, go with Waffle weave MF towels and CB to dry, MF towels with ammonia free cleaner for windows (no streaks) and MF towels for initial buffing of wax, polish, etc. followed by flannel towel buff for bling bling shine.