Ignition control methods for nitrous

[guitaraholic]

After doing a bit of research, I've learned that most people use MSD to retard the timing for nitrous injection. I think they cost near $300 (please correct me if I'm wrong). For $100 more I can get fuel and spark control from AEM (if its yet available for the SR).

Is there any other method to control ignition timing without dumping $300-$400? I know its not that expensive, but it kind of is for something I might only use 5 or 6 times a year. I plan on running between 75-100 wet shot. I got a dry shot system for cheap ($125), and will convert it to wet before installing. I don't plan on using it very much at all, maybe against a few of the V8's I come against. Yes, I know about the supporting mods for that kind of power (ie clutch, lsd, fuel pump ect)

Here's my current engine setup

- S14 Sr20det (stock T28)
- FMIC (HDi)
- Full 3" Exhaust
- Z32 Maf
- 550 Injectors
- Chipped ECU
- Stock Fuel Pump (upgrading in a few days)
- Stock FPR (do I need to upgrade?)

I am getting my car tuned after the fuel pump so I am estimating around 260hp, with a 75-100 shot, it would bring it close to 330-360.

Thanks for all your inputs.