So for all those vacuum lines, do I just pick a thickness (3, 3.5, or 4mm) and replace?You don't have to buy the OEM stuff though. 3, 3.5, and 4mm vacuum lines will work just fine. If you buy silicone replacements, they will stay soft and last a long time too.
IMO, the silicone will stretch out, it looks like it's 5mm but 4mm will work as well. The 3mm is a bit harder to stretch out that far.Is this one 5MM hose or 3MM hose?
Also, regarding the T-fittings, how many are there and what size are they?
When I replace my vacuum hose I want to replace the T-fittings as well.