a few parts pros and cons questions

i am considering a few things for my truck (it has a ford vulcan[3.0 V6]) and wanted some input before i started putting money and time into either.

i currently have a metal upper intake manifold, but have found plastic versions of the same thing for the same engine for the same year... but i am a little worried about any problems that could arrise from converting i.e. cracking, melting, so on (if i do switch to plastic i will expand the ports on it for good measure and extra flow) pros? cons?

i currently have a stock ignition coil but am considering upgrading, possibly to accel, any pros, cons, or other brand reccomendations(so far accel is the only company i can find that makes one for my engine)

and last but not least i have a hard top tonneau cover and am considering removing that and the drop in bed liner and putting in a roll on liner. pros? cons? yes? no?

i currently have a metal upper intake manifold, but have found plastic versions of the same thing for the same engine for the same year... but i am a little worried about any problems that could arrise from converting i.e. cracking, melting, so on (if i do switch to plastic i will expand the ports on it for good measure and extra flow) pros? cons?
There are very few cons with the plastic intake plenum, but also almost no pros. Increased plenum port flow means nothing if you don't improve the flow of the lower intake and head ports. If what you have isn't broken, don't change it.

i currently have a stock ignition coil but am considering upgrading, possibly to accel, any pros, cons, or other brand reccomendations(so far accel is the only company i can find that makes one for my engine)
Again... if it ain't broke, don't fix it. Accel makes mid-grade coils. Even with the best coil on the market, you won't really notice much (if any) difference. When your stock coil starts failing, then consider an aftermarket upgrade.

and last but not least i have a hard top tonneau cover and am considering removing that and the drop in bed liner and putting in a roll on liner. pros? cons? yes? no?
Totally personal preference. I have a soft tonneau on one of my trucks because I use it for keeping some things dry while I tow my travel trailer. My other truck has a utility camper/cap because I use it for work. My personal opinion is that drop-in liners just suck. They are slippery which means things slide around, and the friction between the liner and the bed just eats away at it like sandpaper. In 1988 I bought a brand new Chevy K2500 and put a bedliner in it to protect the bed. I took it out 145k later to find that it had actually worn THROUGH two spots in the bed. My work truck has a Rhino Liner in it and I'm convinced it is worth every single penny.