Several points for you to consider really:-
1 The Rover engined +4s are more difficult to upgrade and source parts than the later Duratec engined +4s , however you would certainly need a larger budget for these. Duratecs give a nice blend between the larger engined Roadsters and trad +8s , and the smaller more nimble 4/4s
2 Don't write off the 4/4 just yet. Have you tried a Sigma engined car , the engine is a peach, it loves to rev and is very "chuckable" , perhaps not the optimal choice for touring , but great fun and you will enjoy every mile.
3 Also don't believe everything you read about the +8. Yes it is much less frugal than your 4/4 ,(25 to 28 mpg for FI models , much less for carb equipped) but if you only cover the "normal 3000 to 5000 miles annually is that such a big factor?
The torque is amazing, and it will pull all the way from 1,500 rpm right up to 5000 where it starts to run out of breath (at which point you are travelling rather rapidly!) with a glorious soundtrack which can be addictive.
Most parts for the Rover engine are readily available , and you can gain some pretty cheap horsepower/torque with upgrades to exhaust manifolds , air intake system, fuel chip (on FI cars) or carb needles on carb equipped
They do feel "big" (especially compared to a 4/4) and the LSD equipped axle can take some familiarisation , but probably no problem to someone well versed in pre-war cars
4 Do you travel into any low emission zones regularly? Most 4/4s and +4 post 1995 (?) will be compliant , but the +8 does not become so until after 2002 when the GEMS engine management was introduced , and these cars are more pricey of course.
5 Do you live in an area infested by speed bumps , if so the early Roadster has VERY low ground clearance , and although the sump modification certainly helps , the clearance of the trad +8 is better.
Tim Ayres at New Elms has raced a +8 for some seasons and knows his way around them , he would be a good person to talk with about the +ves and -ves .
