Paul, to be very honest, a 2litres capacity engine without variable cams has it's limits concerning torque. If down or mid torque is what you are missing... I can be wrong... but I see a slight contradiction between getting softer cams in combination with Throttle bodies. TB will get the best of it at higher revs. And in addition you would start a probably not before proved experiment when changing the cams. At the end it could be costly and it is not guaranteed that it will work properly.
On the other hand, any 4 pot will be significantly lighter than a 3.7V6 Roadster. It is the old dilemma. If I could have a 180 HP engine full of low and mid rev torque but not heavier than my 4/4 it would be the best Mog I could think about.
I don't know which style of driving you prefer, if it is cruising, go for a Roadster. If you like a little bit more agility and nimble curve behave go with four pots.
If I were you I would also scan if there is a good serviced used P4SS available. I drove 23.000 km with one. While having TBs as well as the ARP4 the mid torque from 2.500 on and high rev torque of the P4SS was really very good due to the variable intake camshaft.
and here on TM were morer stories posted about the last update of the P4SS which made them really cool and even more powerful which I would like to experience sometime if possible.
Of course I'm biased to see the benefits of the P4SS and forgive me proud owners of a ARP4, I never drove one, sorry for that and I think there are many happy drivers of ARP4 existent. So many different solutions for so many different needs.
One solution (for me, just playing with possibilities) could be an additional rotrex charger to add to my Sigma engine, only to boost very gentle and save with low pressure, but that is another story...
