If you're not going to put a lot of power in it, i wouldn't get the steel outdrives yet.
a Mate runs the db-01R with the original outdrives on our clay track with a 6.5 and he hasn't had any issues so far.
Carpet would probably be a different story.
I also order a lot of stuff at Seidel as no lhs stock TRF parts(or db-01 parts for that matter).
I don't know how fast he delivers to the UK but to NL it's between 3-4 days usually.
*I just noticed you're from belgium so that should be 3-4 days.
PS.
Get black wheels. White and yellow are outdated.