The CJ4A Chassis is competent and in my not at all humble opinion was related to the best Lancer Evo ever. the 6.5
The Megans seem like an okay choice with Front Spring Rates of 335# and rear of 250#. not race car stiff but better then most, and WAYYYY stiffer then stock.. For refrence the Tein S-tech spring kit is only 168#F and 129#R (and they usually run 10-20% over stock) so the megan is going to handle A LOT better and be less likley to bottom out.
However with power comes responsibility, when springrates of 250% of stock are used the way the chassis and suspension responds to bumps changes dramaically, i won't bore you with complex mathamatical equasions to explain optimum damping cruves, but the simple fact is stock just won't cut it, neither will most basic aftermarket peices. in addition your shocks have to work extra hard since they have a Heavy lump of steel bolted to them in the form of a steel wheel, increases in unsprung weight increase damping requirements quite a bit.
but your main concern is to find a part with a lot of Rebound damping to control those springs and keep you from flying into a tree on the outside of a spirited corner.
Since price is a Major object I would recommend the Koni Yellow's (strut inserts for the front, and eye to pin's in the rear) There are lots of exotic hardware available for this chassis (it was a very popular racer in it's day) but Koni is about as good as you can get within a modicum of a budget. unless you can find some old stock Ralliart dampers, but I think they have been out of production for a while.
Koni Pricing
8610-1343 Sport (Front Strut application)
$166 each
Rear application
80-2714 Sport (Rear Shock assy)
$122 each
Now there is a KYB AGX application for the rear,
which you can buy cheaper then I can directly from summit
KYB 741033 - KYB AGX Adjustable Gas Shocks and Struts - summitracing.com
But for $68 more I'd get the koni's all around, it's a better damper. Plus it's Rebuildable/Revalvable so it can grow with you and the car if you ever decide to race it and you'll never need to buy another shock. plus if you buy locally you don't have to pay shipping. so the diffrence is less then $60