You can research for years, you can set your minimum requirement for the car to the point that only a few cars in the world match it, but in the end all you are doing is depriving yourself of driving the greatest car on the road.
I make less money than most people here so I am not one of the rich who can afford to buy a 360 and throw it away a few months later. My 360 is the single most expensive item I have ever purchased. I wanted a Ferrari since high school in the mid-1970's and saved money for first a 246 GTS to replace my FIAT Dino with, then it was a 308 GTS, then a 328 GTS, that is all I wanted a 328 GTS. Early last year I decided it was time to sell the FIAT Dino and finally buy my Ferrari. I looked around at many 328's over the course of a month or so. I made a offer on a 328 $4k below the asking price but $2k to $4k ABOVE what I thought the car was worth because I wanted the color, the owner instead of counter offering put it on ebay. That was the end for me (it finally sold for less then my offer about 5 months later). My wife said lets move up a 360, I think it was Tuesday, Thursday I made the offer on my un-seen 360 and the owner accepted, done I owned a Ferrari (if the car passed PPI, which I ended not doing anyway). My car had been on the market only a few days.
My list was short... NOT Red or Black, prefer stick over F1 but either way would work for me.
I now am upset at the years I kept the Dino instead of selling it and getting a Ferrari, I am upset at the pleasure I lost by not driving a Ferrari all that time and I wish I had done it years earlier. Yeah, if I had done it earlier it would have been a 3x8 since I could not have afforded a 360.
The more expensive of the two MG cars you mentioned would be PERFECT for me. But, am I gonna call and start negotiating a deal with them? Not likely, because they have it priced so unreasonably that we're not even in the same ballpark. So, I'd rather not waste my time.
The time it takes to make a offer is what ? maybe 2 minutes on the phone with the qualification that the car has to pass PPI, that is not a waste of time, if you are that far off they will likely tell you to go fly a kite, thank them for their time and remind them of your name and number should they decide to sell the car in the near future and you are done. Its a car dealer, a car dealer has no feelings to hurt, you can't hurt their feelings, so it hurts nothing to spend 2 minutes trying.
These cars like all cars have a price, the range is actually quite small for each year. The dreamers can ask all they want for the car and maybe they will find that elusive sucker but more likely they will eventually come down to the price.
a 99 Modena should be worth $60 to 70K, add $5k for each year after that bringing a 05 Modena to $90 to 100, add $10k for a spider and voila you have your range, anything below that buy it now it wont last long, anything above that is a dreamer. Yes there will be exceptions, there always are. There will also be some details like a 99 with a updated TCU might be worth a few k more than the above rule, some exhausts might add $2k but the range still remains small and fairly fixed. Some prefer lower mileage and will pay a few k more for that, some others prefer a properly used car.
The goal should be get in a drive NOW not in a few years when you finally get around to it.