PG 93 of the Mongoose Core Rule book. List 4 types of medkits but doesn't tell you what bonuses, if any, you get for each tech level. Am I missing something?
It does not give bonuses. It just provides the medic the stuff he needs in a portable case. He will get penalties if he tries to treat people without the equipment he needs.
'Higher-technology medikits do not give a bonus to basic treatment, but can help with more exotic problems or when treating augmented individuals'
Its in there - treating augmented individuals may benefit by offsetting the TL DM (see pg 76). This would likely also be applicable for treating Aliens which are Engineered.
The specific contents of any kit are undefined. However, drugs are listed with TLs - so you can use that as a guideline - ex: FastDrug (TL 10) would not be standard in a TL8 medikit.
Any kit can give a +1 DM (see skill section), though that is a Ref call - in many cases one might require a medikit (so no +DM) - and make any attempt without more difficult (or near impossible). Ex: one can render first aid without a medikit - but it would be more effective (+1 DM) with one, IMO.