As a long time Detroit Techno producer myself I can give you some really good recomendations for Synths and FX/Mastering tools. Please see my recomendations below:
Instruments
Ohmforce Minimonsta (Great for detroit techno basslines and pads)
Native Instruments Reaktor (I use it to create my percussion tracks, the 'Newskool' ensemble is great.
Korg Legacy Polysix
Native Instruments FM8 (Used mainly for loading up old DX7 presets such as 'Solid Bass')
Audiorealism Bassline (For some acid basslines)
Arturia Prophet/Jupiter/Moog Modular (For fx sounds, transitions etc)
FX
FabFilter Timeless (Amazing delay plugin, I use it on nearly every track I produce)
PSP85 (Another great delay plugin capable of transforming sounds)
Filterbank Pro (Great for lovely old school filtering)
Nebula Space Reverb (Real analogue reverb with nice realtime control)
ModVerb (A highly versatile reverb, great for Detroit percussion)
Mixing and Mastering
Punch Compressor - 1176 emulation (Used on all my drum and percussion tracks)
FabFilter Pro-Q - Fantastic EQ that I use all of the time
MSI Stereo Buss Compressor - Nice SSL emulation used on the master track to glue everything together
I hope that helps
