you have a sizeable budget
its your railway and you should run whatever you like
im not sure exactly which style cars you have purchased
the harz, if you like its blocky styling-I have one and its very nice loco, ok pulling power, better with added weight
I like the 2095/2096-austrian OBB diesel too, and it pulls well
the DB 2050 diesel, also two motor, kinda boring but a very nice running loco-these are used not only on the HB but also the Rugen (which are the two cars tyles similar to the NQ car offerings)
and
a green mallet 2080 is always a joy as well-massive
even the zillertall 0-6-2 and the French loco 0-6-0-both pull quite nicely
at the top of your budget would be the Frank S locos-powered tender and really lovely-possibly the best prototype match in terms of actual car styles (Rugen style with flatter of the two roofs styles) and a loco which ran on the Rugen line
I have all of these and I have no reservations about any-the zillertall, imho, has rather delicate running gear in places, (the upper exhaust slide pistons), but otherwise is a fine workhorse loco-they are rather common and can be a good value-I prefer the later styles as they have 5 volt lighting and smoke -and, plastic running gear
all would/should be within your budget