Throttle Body Spacers

I am just now thinking of doing some minor upgrades to the motor in my 99 Jeep Cherokee. I was wondering if anyone had some advice and or opinions on installing a throttle body spacer on the 4.0L engine? Also what brand of cold air intake does anyone suggest? Thank you for your time.

Got my TB spacer and new bored out TB from Rock-it Parts and I use the K&N filter and Air Tube combo from Rusty's Off Road----Both are great and I do feel a Horsepower Surge when accelerating

A poweraid spacer and an ARB snorkel gave water resistant cold air and power to my 89.