what do you consider "degrading" the engine. Technically just driving the car stock is degrading the engine since it wears on it over time. Anything that adds HP is going to stress components more than stock.
Anyway... get a tune. jb4 second hand would be cheap. Meth is always a good boost for cheap(but not my thing). After that the cost/HP increases but would be intercooler and downpipes.
EDIT: I forgot about DCI.