I own a 92 maxima and a 94 gsr at the moment (the gsr will be replacing the max). I just got the gsr a couple weeks ago, but Ive had the max for some time now, so i will splurge about it.

maxima:

90-91 se (and 92-94 gxe) has the vg engine... it is 160hp iron block. very reliable engine but a tad slow (ive got 163k+ on mine and there's a guy on maxima.org with over 400k miles on the original engine)
92-94 se comes with 190 hp aluminum block, its got umpf but the VTCs (kinda like vtec) tend to fail... so make sure it doesnt make a ticking sound on a cold start. It's a good indication they are going to eventually fail. You can either disable the vtcs by grounding them (free fix) or have them replaced, $1000+

Other common failures to look out for both engines are:
exhaust studs breaking - can be costly to fix (labor)
window regulators
antenna mast

If you are going to get a maxima, be sure to get a manual (and they are hard to come by so keep looking). Their automatics are not the greatest transmissions.

There are no "bolt-on" turbos or superchargers for the 3rd gen maxima.

that said, they do respond to mods quite well. An intake and exhaust (y-pipe) and people have dynoed 15-20hp increase... mainly because the y-pipe is poorly designed. It's not unheard of to get a 3rd gen max (ve) in the mid 14s quater mile w/o any forced induction. They are sleeper sedans, esp the 4th gen max =)

3rd gen maximas have rear independent suspension. 4th gen and up don't. So if you slap on some aftermarket shocks/springs and front and rear strut bars, it can be a decent handler, mind you it is a 3100+ lbs sedan. Like all fwd's it tends to understeer.

In comparison I like both cars but they both have their tradeoffs. I like the Maxima for the comfort, roominess, plenty of torque. Integra just looks cooler (I've gotten compliments already), huge aftermarket, good handling, good turn radius.