Dear sir your answer is extremely valuable for me, are you 100% sure about the compatibility of the parts ? especially needle/nozzle
Please, don't call me "sir"
I've just checked up
Fluid nozzle and air nozzle are like for HP-C (0.3mm), but the needle is like for models A, B, SB, this one has smaller diameter than C model's. Check up your brush for that, I mean the needle.
Originally, if to use 0.3mm nozzle and 0.2mm needle combination, the needle would stick out off the nozzle longer than usual. I solved the issue by sanding down the tip a bit with fine grit sandpapers on a piece of glass and polished the tip after the sanding. If you have some experience in repairing your airbrush needles tips, that not an issue for you.
Another variant is to buy needle screw with teflon packing for HP-C+ and change it instead the one installed originally. In this case you can use fluid nozzle, air nozzle and the needle all for HP-C model, without any sanding the tip. Needle packing for HP-C+ works with urethanes also. Originally, Olympos would come with rubber needle packing. I've changed all the packing in my Olympos airbrushes.
But if you'd use your 101 with urethanes, it's also better to change the side cup. It may be original from Olympos or using Grex adaptor you can use all range of Iwata cups making your 101 either gravity feed or siphon feed airbrush.
Olympos cups have bigger tube than Iwata.
I find plug in type of cups much more convenient than screwing in type side cups.
Concerning internals of 101 model - they're not like other models. You have the brush, so you know what I'm talking about.
You can see the difference between Olympos and Iwata cups.
Olympos cup I also bought separately, as airbrush comes with screw in type cup.
Here's what you could use with your Olympos.