my plans for upgrades are as you say an engine upgrade, a new dash with individual gauges & generally nice parts that i can,t afford during the actual build of the car, ie better headlights (carbon ones ) & poss new wheels & tyres.
Then it,ll be time to start building the single seater
instead of heated seats just wear some thermal longjohns
are you planning on using your car thru the winter?
cheers
andy