I'm looking to get a 90 GSX with a ton of mods, and in really good shape. But I was wondering if they are reliable cars, and what is the average MPG for these cars?

 

well they are reliable if they are stock and you keep up on what needs to be taken care of and dont beat it to ****. since your want one with mods, chances are its not gonna be reliable. on a 1g gsx the stock fuel economy is around 25 mpg highway i believe, dont quote me on that, but if your getting one with mods, that all changes once again. if you have tons of mods done to it then the fuel economy is going to be s h i t t y

 

Lol, well said Estraw...
There's a couple things that don't and won't match up. Mods and reliability. They can mate up just fine if the mods are done correctly and in some instances, in order. This just doesn't happen much anymore.
As Estraw stated, whether, stock or modded, if the car is abused..it's going to be unreliable.
You will either need to already know how to work on cars, have enough money to give to a shop, or you will learn to work on it yourself....<--that's more gratifying IMO.
If you're worried about MPG..I don't recommend turbo cars since they are so easily modifiable in a way to reduce MPG. To add on to that...a poorly maintained non-turbo car will lose MPG...add forced induction into that scenerio and you've lost even more MPG.

Rule of thumb...
You can't have a fast, modded, reliable car with good MPG.
..and you can't have a car that is fast, reliable and cheap...do you follow me?
The first one just can't happen unless the motor can shut off 2 cylinders while you're cruising like today's Hemis can do. The only thing is, these motors have 4 cylinders and not 8.
The last one can only have two of the three but not all three at the same time.

 

if your looking for speed go ahead but as previously stated, it probably wontbe too reliable..and more than likely your gas milage will also suck

 

the faster mine gets, the more its in the garage with the hood open or being drug home with the transfer case half torn off & draggin the road[:@]
i must be missing something because i can get close to 40MPG out of my car when i keep my foot out of it. use it and it goes down to about 8 mpg