Good morning Damian,
I reflect everything mentioned above.
I moved into the seven scene after owning many classics, MGBGT, MGB Roadster, Triumph Stag, several 70's and 80's minis... Etc. When it comes to modern tin tops they're a bit lifeless to drive. My Afla 156 GTA was ok, but I really found the S2000 a bit detached from reality. So more in it for the drive, as a practical and safer bike replacement also, hopefully, wasn't going to leave vital fluids everywhere. I started with a 1600 pinto Rovin Hood, was pretty good, but 85ish horses didn't last long. Then I moved to a 2.0 pinto, huge spec and a T3 turbo have me 217bhp. I found this far too much. I had the car 14 months and always found the chassis couldn't handle the power. I got my Westfield, 1800 Zetec on carbs, 150ish horses and it was so well balanced and a perfect drive. I drove 2.0 zetecs, injected 1800's, CVH's and other seven style cars and found the 1800 Zetec matched what I wanted each time. I've considered "just changing the cams" which could give me an easy 180ish and be a few hundred pound. But as a car I use to enjoy a summers day and have fun driving coastal roads it's rare I feel the need for more power.
However I know of owners here that have over 250 horses, use their cars on track days and want more power and do everything to shed the odd kilo. So you need to think what you use the car for first. I considered getting a S2000 powered westfield for a couple of years, but I would never need that power and feel it would be too much for the chassis to handle... Well my driving ability at least!
Good luck in your search and remember, buyers market! Believe me, you'll know the right car. When I got mine it was 7yrs old and had 1678 miles on the clock. Basically used for a show a year and to/from MOT. Not much else. I covered more than that in the first month of ownership!
Stephen