hi max
y are you wanted to change the dash clocks?
comfy seats??? depends how much work you want to do you can fit almost any seat with a bit of welding or spanner work
honda civic, astra gte, ford secort, ford fiesta, are the most popular that are fitted.
only something like a janspeed manifold and exhaust is likely to put a bit more grunt but not much tbh, again with a bit of spanner work you can drop in a 1.3 is your 410 the 4 or 5 speed version?
gen-x