According to the on-line Oxford dictionary, "GT" ("Gran Turisimo") refers to, "A high-performance
model of
automobile. Hence the "GT" designation on my PT cruiser is entirely appropriate. The "GT" version had a 230HP engine, vs the 150HP of the base model or 180HP for the light-pressure turbo. For comparison, the base Subaru WRX, which weighs about the same, has/had about 225HP, and is a "high performance" car by any rational definition.
230HP is usable power. It allows, for example, easily merging from a stop sign onto a freeway with traffic traveling at 60mph or more. Passing an 18 wheeler quickly is no problem. It is not strained at 70 or 75mph, as the base car would be.
Paying a premium for, say, 300HP MORE THAN A BASE car is pointless, stupid, and - I would argue - a manifestation of some deficiency in the purchaser's psyche. I used "small penis" in jest, but the point is valid. It is the automotive equivalent of wearing a thick gold chain or a flashy Rolex watch or large diamond-stud earring. If you want luxurious, safe transportation with some "sporting" capabilities, anything over 400HP is ludicrous.
And keep in mind, these cars are not "investments" in any sense of the word. When driven off the lot they depreciate at least $10-20 thousand dollars, and their three-year depreciation alone would, in most cases, pay for a new luxurious sedan, adequate for any sane purpose.