Welcome aboard mate!
I had a 156 V6 and it was great performance wise but returned me 22MPG at best,
I think the best choice is the 2 Litre Twin Spark, as it combines stunning performance with decent fuel economy. Late 20's, early 30's MPG wise perhaps???
If you buy one mate, remember that the cambelt needs changing every 36,000 miles or every 3 years, whichever comes sooner. And it aint cheap, about £400 maximum? So try and buy one that has already had it done, or ideally buy a cheaper 156 and just knock the price down to budget for one.
I'll tell you what you should get: 1998 156 2.0 TS with SP package. The SP pack comes with better wheels and side skirts, and if you can try and find one with a factory spoiler on, one of the big ones, they look great. You can tell if it is an SP because the speedo will have a black backing instead of white.
The SP comes with better suspension making it GREAT in the corners!!!
Greater than it already is!!!
They really are great cars mate, and if you can pick one up that has full history AND had a recent cambelt change with about 80K on the clock, circa 1998, expect to pay no more than £2000 I reckon. The V6's go for a fair whack more usually in similar condition, mileage.
But yeah, the 2 Litre TS is plenty quick enough, especially if you have a Puma at the moment.